Statistics Question: Revenue & Cost
$begingroup$
Data for costs of production for a firm every month from January 2001 to December 2002. Data is denoted by $d_1, d_2,...,d_{24}$. The following info is calculated from the data set.
Mean cost = $2500, Range of Costs = $7500, Sample Standard Deviation of Costs = $5500.
Relationship between Cost and Revenue is given by $R_i = -7d_i + 1000, i = 1,2,...,24$.
Answer the following:
- The average revenue for our data set is ....
- The Range of the Revenue is ....
- The variance in revenues of the data set is ...
Answers:
- -$16,500
- $52,500
- $38500^2$
Can someone help explain this to me how they got these numbers, I have already been trying to come up with a solution.
statistics standard-deviation
edited Feb 5 '13 at 11:21
Raskolnikov
12.5k23571
asked Feb 5 '13 at 8:32
user61049user61049
135
$endgroup$
add a comment |
$begingroup$
Data for costs of production for a firm every month from January 2001 to December 2002. Data is denoted by $d_1, d_2,...,d_{24}$. The following info is calculated from the data set.
Mean cost = $2500, Range of Costs = $7500, Sample Standard Deviation of Costs = $5500.
Relationship between Cost and Revenue is given by $R_i = -7d_i + 1000, i = 1,2,...,24$.
Answer the following:
- The average revenue for our data set is ....
- The Range of the Revenue is ....
- The variance in revenues of the data set is ...
Answers:
- -$16,500
- $52,500
- $38500^2$
Can someone help explain this to me how they got these numbers, I have already been trying to come up with a solution.
statistics standard-deviation
edited Feb 5 '13 at 11:21
Raskolnikov
12.5k23571
asked Feb 5 '13 at 8:32
user61049user61049
135
$endgroup$
$begingroup$
I'd like to know how they got those numbers too. I don't mean the numbers in the answers (those are easy), I mean the numbers in the question: the mean, range, and sample standard deviation of cost. I do not see how the values given for those three numbers can possibly occur together.
$endgroup$
– David K
Oct 13 '15 at 5:19
add a comment |
$begingroup$
Data for costs of production for a firm every month from January 2001 to December 2002. Data is denoted by $d_1, d_2,...,d_{24}$. The following info is calculated from the data set.
Mean cost = $2500, Range of Costs = $7500, Sample Standard Deviation of Costs = $5500.
Relationship between Cost and Revenue is given by $R_i = -7d_i + 1000, i = 1,2,...,24$.
Answer the following:
- The average revenue for our data set is ....
- The Range of the Revenue is ....
- The variance in revenues of the data set is ...
Answers:
- -$16,500
- $52,500
- $38500^2$
Can someone help explain this to me how they got these numbers, I have already been trying to come up with a solution.
statistics standard-deviation
edited Feb 5 '13 at 11:21
Raskolnikov
12.5k23571
asked Feb 5 '13 at 8:32
user61049user61049
135
$endgroup$
Data for costs of production for a firm every month from January 2001 to December 2002. Data is denoted by $d_1, d_2,...,d_{24}$. The following info is calculated from the data set.
Mean cost = $2500, Range of Costs = $7500, Sample Standard Deviation of Costs = $5500.
Relationship between Cost and Revenue is given by $R_i = -7d_i + 1000, i = 1,2,...,24$.
Answer the following:
- The average revenue for our data set is ....
- The Range of the Revenue is ....
- The variance in revenues of the data set is ...
Answers:
- -$16,500
- $52,500
- $38500^2$
Can someone help explain this to me how they got these numbers, I have already been trying to come up with a solution.
statistics standard-deviation
statistics standard-deviation
edited Feb 5 '13 at 11:21
Raskolnikov
12.5k23571
asked Feb 5 '13 at 8:32
user61049user61049
135
edited Feb 5 '13 at 11:21
Raskolnikov
12.5k23571
asked Feb 5 '13 at 8:32
user61049user61049
135
edited Feb 5 '13 at 11:21
Raskolnikov
12.5k23571
edited Feb 5 '13 at 11:21
Raskolnikov
12.5k23571
edited Feb 5 '13 at 11:21
Raskolnikov
12.5k23571
12.5k23571
asked Feb 5 '13 at 8:32
user61049user61049
135
asked Feb 5 '13 at 8:32
user61049user61049
135
asked Feb 5 '13 at 8:32
user61049user61049
135
135
$begingroup$
I'd like to know how they got those numbers too. I don't mean the numbers in the answers (those are easy), I mean the numbers in the question: the mean, range, and sample standard deviation of cost. I do not see how the values given for those three numbers can possibly occur together.
$endgroup$
– David K
Oct 13 '15 at 5:19
add a comment |
$begingroup$
I'd like to know how they got those numbers too. I don't mean the numbers in the answers (those are easy), I mean the numbers in the question: the mean, range, and sample standard deviation of cost. I do not see how the values given for those three numbers can possibly occur together.
$endgroup$
– David K
Oct 13 '15 at 5:19
$begingroup$
I'd like to know how they got those numbers too. I don't mean the numbers in the answers (those are easy), I mean the numbers in the question: the mean, range, and sample standard deviation of cost. I do not see how the values given for those three numbers can possibly occur together.
$endgroup$
– David K
Oct 13 '15 at 5:19
$begingroup$
I'd like to know how they got those numbers too. I don't mean the numbers in the answers (those are easy), I mean the numbers in the question: the mean, range, and sample standard deviation of cost. I do not see how the values given for those three numbers can possibly occur together.
$endgroup$
– David K
Oct 13 '15 at 5:19
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
I didnt understand the part (b). However part (a) and (c) are straightforward.
$(a)$ For $24$ data you are given the mean cost that is $2500$$. If you want to calculate the average Revenue, then you can write it in a formula: $$frac{1}{24}sum_i R_i$$ so $1000frac{1}{24}*24=1000$ and for the first term you have $-7sum_i d_i/24$ here you are given what $sum_i d_i/24$ is; that is the mean cost which is $2500$$. So you can do the rest.
(b) Here you are asked to calculate the variance. If you multiply a data with a number which is $7$ here, then what happens to its variance? So if you subtract some value from you each element of your data then the variance will not be affected. Becase it doesnt afffect how your data $changes$. However if you multiply each element of your data then what happens? you have the sample variance as follows $$frac{1}{24}sum_i (d_i-mu)^2.$$ If you multiply with $7$, then you get $$frac{1}{24}sum_i (7(d_i-mu))^2=7^2frac{1}{24}sum_i (d_i-mu)^2.$$ Since you are given the standard deviation $$sqrt{frac{1}{24}sum_i (d_i-mu)^2}=5500$$$ then when you plug in this result to the above given equation, you get $$7^25500^2=(7times5500)^2$$
answered Feb 5 '13 at 11:16
Seyhmus GüngörenSeyhmus Güngören
5,57131736
$endgroup$
$begingroup$
Part b) is just a rescaling and shifting of the range of Costs with the formula that gives the relation between costs and revenues.
$endgroup$
– Raskolnikov
Feb 5 '13 at 11:23
$begingroup$
@Raskolnikov isn't it just the scaling? Now I guess the range is where the data lies. When the data is multiplied by $7$ then the range is also multiplied by $7$, indep. of the shifting I guess.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 11:34
$begingroup$
Yes, you're right. I actually had the lower and upper bound of the range in mind when I made the comment. But if we're just talking about the width, scaling is enough.
$endgroup$
– Raskolnikov
Feb 5 '13 at 12:05
$begingroup$
Can you explain your a) and b) please? I still do not see it
$endgroup$
– user61049
Feb 5 '13 at 15:08
$begingroup$
@user61049 in part (a) you will multiply $2500$ with $-7$ and then add $1000$. In part (b) you will multiply the range $7500$ with $7$ and in part (c) you will multiply the standard deviation $5500$ with $7$ and then take the square of it. Tell me the unclear parts if there are and then i think about another way of explanation.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 18:44
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f295283%2fstatistics-question-revenue-cost%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
I didnt understand the part (b). However part (a) and (c) are straightforward.
$(a)$ For $24$ data you are given the mean cost that is $2500$$. If you want to calculate the average Revenue, then you can write it in a formula: $$frac{1}{24}sum_i R_i$$ so $1000frac{1}{24}*24=1000$ and for the first term you have $-7sum_i d_i/24$ here you are given what $sum_i d_i/24$ is; that is the mean cost which is $2500$$. So you can do the rest.
(b) Here you are asked to calculate the variance. If you multiply a data with a number which is $7$ here, then what happens to its variance? So if you subtract some value from you each element of your data then the variance will not be affected. Becase it doesnt afffect how your data $changes$. However if you multiply each element of your data then what happens? you have the sample variance as follows $$frac{1}{24}sum_i (d_i-mu)^2.$$ If you multiply with $7$, then you get $$frac{1}{24}sum_i (7(d_i-mu))^2=7^2frac{1}{24}sum_i (d_i-mu)^2.$$ Since you are given the standard deviation $$sqrt{frac{1}{24}sum_i (d_i-mu)^2}=5500$$$ then when you plug in this result to the above given equation, you get $$7^25500^2=(7times5500)^2$$
answered Feb 5 '13 at 11:16
Seyhmus GüngörenSeyhmus Güngören
5,57131736
$endgroup$
$begingroup$
Part b) is just a rescaling and shifting of the range of Costs with the formula that gives the relation between costs and revenues.
$endgroup$
– Raskolnikov
Feb 5 '13 at 11:23
$begingroup$
@Raskolnikov isn't it just the scaling? Now I guess the range is where the data lies. When the data is multiplied by $7$ then the range is also multiplied by $7$, indep. of the shifting I guess.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 11:34
$begingroup$
Yes, you're right. I actually had the lower and upper bound of the range in mind when I made the comment. But if we're just talking about the width, scaling is enough.
$endgroup$
– Raskolnikov
Feb 5 '13 at 12:05
$begingroup$
Can you explain your a) and b) please? I still do not see it
$endgroup$
– user61049
Feb 5 '13 at 15:08
$begingroup$
@user61049 in part (a) you will multiply $2500$ with $-7$ and then add $1000$. In part (b) you will multiply the range $7500$ with $7$ and in part (c) you will multiply the standard deviation $5500$ with $7$ and then take the square of it. Tell me the unclear parts if there are and then i think about another way of explanation.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 18:44
add a comment |
$begingroup$
I didnt understand the part (b). However part (a) and (c) are straightforward.
$(a)$ For $24$ data you are given the mean cost that is $2500$$. If you want to calculate the average Revenue, then you can write it in a formula: $$frac{1}{24}sum_i R_i$$ so $1000frac{1}{24}*24=1000$ and for the first term you have $-7sum_i d_i/24$ here you are given what $sum_i d_i/24$ is; that is the mean cost which is $2500$$. So you can do the rest.
(b) Here you are asked to calculate the variance. If you multiply a data with a number which is $7$ here, then what happens to its variance? So if you subtract some value from you each element of your data then the variance will not be affected. Becase it doesnt afffect how your data $changes$. However if you multiply each element of your data then what happens? you have the sample variance as follows $$frac{1}{24}sum_i (d_i-mu)^2.$$ If you multiply with $7$, then you get $$frac{1}{24}sum_i (7(d_i-mu))^2=7^2frac{1}{24}sum_i (d_i-mu)^2.$$ Since you are given the standard deviation $$sqrt{frac{1}{24}sum_i (d_i-mu)^2}=5500$$$ then when you plug in this result to the above given equation, you get $$7^25500^2=(7times5500)^2$$
answered Feb 5 '13 at 11:16
Seyhmus GüngörenSeyhmus Güngören
5,57131736
$endgroup$
$begingroup$
Part b) is just a rescaling and shifting of the range of Costs with the formula that gives the relation between costs and revenues.
$endgroup$
– Raskolnikov
Feb 5 '13 at 11:23
$begingroup$
@Raskolnikov isn't it just the scaling? Now I guess the range is where the data lies. When the data is multiplied by $7$ then the range is also multiplied by $7$, indep. of the shifting I guess.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 11:34
$begingroup$
Yes, you're right. I actually had the lower and upper bound of the range in mind when I made the comment. But if we're just talking about the width, scaling is enough.
$endgroup$
– Raskolnikov
Feb 5 '13 at 12:05
$begingroup$
Can you explain your a) and b) please? I still do not see it
$endgroup$
– user61049
Feb 5 '13 at 15:08
$begingroup$
@user61049 in part (a) you will multiply $2500$ with $-7$ and then add $1000$. In part (b) you will multiply the range $7500$ with $7$ and in part (c) you will multiply the standard deviation $5500$ with $7$ and then take the square of it. Tell me the unclear parts if there are and then i think about another way of explanation.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 18:44
add a comment |
$begingroup$
I didnt understand the part (b). However part (a) and (c) are straightforward.
$(a)$ For $24$ data you are given the mean cost that is $2500$$. If you want to calculate the average Revenue, then you can write it in a formula: $$frac{1}{24}sum_i R_i$$ so $1000frac{1}{24}*24=1000$ and for the first term you have $-7sum_i d_i/24$ here you are given what $sum_i d_i/24$ is; that is the mean cost which is $2500$$. So you can do the rest.
(b) Here you are asked to calculate the variance. If you multiply a data with a number which is $7$ here, then what happens to its variance? So if you subtract some value from you each element of your data then the variance will not be affected. Becase it doesnt afffect how your data $changes$. However if you multiply each element of your data then what happens? you have the sample variance as follows $$frac{1}{24}sum_i (d_i-mu)^2.$$ If you multiply with $7$, then you get $$frac{1}{24}sum_i (7(d_i-mu))^2=7^2frac{1}{24}sum_i (d_i-mu)^2.$$ Since you are given the standard deviation $$sqrt{frac{1}{24}sum_i (d_i-mu)^2}=5500$$$ then when you plug in this result to the above given equation, you get $$7^25500^2=(7times5500)^2$$
answered Feb 5 '13 at 11:16
Seyhmus GüngörenSeyhmus Güngören
5,57131736
$endgroup$
I didnt understand the part (b). However part (a) and (c) are straightforward.
$(a)$ For $24$ data you are given the mean cost that is $2500$$. If you want to calculate the average Revenue, then you can write it in a formula: $$frac{1}{24}sum_i R_i$$ so $1000frac{1}{24}*24=1000$ and for the first term you have $-7sum_i d_i/24$ here you are given what $sum_i d_i/24$ is; that is the mean cost which is $2500$$. So you can do the rest.
(b) Here you are asked to calculate the variance. If you multiply a data with a number which is $7$ here, then what happens to its variance? So if you subtract some value from you each element of your data then the variance will not be affected. Becase it doesnt afffect how your data $changes$. However if you multiply each element of your data then what happens? you have the sample variance as follows $$frac{1}{24}sum_i (d_i-mu)^2.$$ If you multiply with $7$, then you get $$frac{1}{24}sum_i (7(d_i-mu))^2=7^2frac{1}{24}sum_i (d_i-mu)^2.$$ Since you are given the standard deviation $$sqrt{frac{1}{24}sum_i (d_i-mu)^2}=5500$$$ then when you plug in this result to the above given equation, you get $$7^25500^2=(7times5500)^2$$
answered Feb 5 '13 at 11:16
Seyhmus GüngörenSeyhmus Güngören
5,57131736
edited Feb 5 '13 at 11:24
answered Feb 5 '13 at 11:16
Seyhmus GüngörenSeyhmus Güngören
5,57131736
answered Feb 5 '13 at 11:16
Seyhmus GüngörenSeyhmus Güngören
5,57131736
answered Feb 5 '13 at 11:16
Seyhmus GüngörenSeyhmus Güngören
5,57131736
5,57131736
$begingroup$
Part b) is just a rescaling and shifting of the range of Costs with the formula that gives the relation between costs and revenues.
$endgroup$
– Raskolnikov
Feb 5 '13 at 11:23
$begingroup$
@Raskolnikov isn't it just the scaling? Now I guess the range is where the data lies. When the data is multiplied by $7$ then the range is also multiplied by $7$, indep. of the shifting I guess.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 11:34
$begingroup$
Yes, you're right. I actually had the lower and upper bound of the range in mind when I made the comment. But if we're just talking about the width, scaling is enough.
$endgroup$
– Raskolnikov
Feb 5 '13 at 12:05
$begingroup$
Can you explain your a) and b) please? I still do not see it
$endgroup$
– user61049
Feb 5 '13 at 15:08
$begingroup$
@user61049 in part (a) you will multiply $2500$ with $-7$ and then add $1000$. In part (b) you will multiply the range $7500$ with $7$ and in part (c) you will multiply the standard deviation $5500$ with $7$ and then take the square of it. Tell me the unclear parts if there are and then i think about another way of explanation.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 18:44
add a comment |
$begingroup$
Part b) is just a rescaling and shifting of the range of Costs with the formula that gives the relation between costs and revenues.
$endgroup$
– Raskolnikov
Feb 5 '13 at 11:23
$begingroup$
@Raskolnikov isn't it just the scaling? Now I guess the range is where the data lies. When the data is multiplied by $7$ then the range is also multiplied by $7$, indep. of the shifting I guess.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 11:34
$begingroup$
Yes, you're right. I actually had the lower and upper bound of the range in mind when I made the comment. But if we're just talking about the width, scaling is enough.
$endgroup$
– Raskolnikov
Feb 5 '13 at 12:05
$begingroup$
Can you explain your a) and b) please? I still do not see it
$endgroup$
– user61049
Feb 5 '13 at 15:08
$begingroup$
@user61049 in part (a) you will multiply $2500$ with $-7$ and then add $1000$. In part (b) you will multiply the range $7500$ with $7$ and in part (c) you will multiply the standard deviation $5500$ with $7$ and then take the square of it. Tell me the unclear parts if there are and then i think about another way of explanation.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 18:44
$begingroup$
Part b) is just a rescaling and shifting of the range of Costs with the formula that gives the relation between costs and revenues.
$endgroup$
– Raskolnikov
Feb 5 '13 at 11:23
$begingroup$
Part b) is just a rescaling and shifting of the range of Costs with the formula that gives the relation between costs and revenues.
$endgroup$
– Raskolnikov
Feb 5 '13 at 11:23
$begingroup$
@Raskolnikov isn't it just the scaling? Now I guess the range is where the data lies. When the data is multiplied by $7$ then the range is also multiplied by $7$, indep. of the shifting I guess.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 11:34
$begingroup$
@Raskolnikov isn't it just the scaling? Now I guess the range is where the data lies. When the data is multiplied by $7$ then the range is also multiplied by $7$, indep. of the shifting I guess.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 11:34
$begingroup$
Yes, you're right. I actually had the lower and upper bound of the range in mind when I made the comment. But if we're just talking about the width, scaling is enough.
$endgroup$
– Raskolnikov
Feb 5 '13 at 12:05
$begingroup$
Yes, you're right. I actually had the lower and upper bound of the range in mind when I made the comment. But if we're just talking about the width, scaling is enough.
$endgroup$
– Raskolnikov
Feb 5 '13 at 12:05
$begingroup$
Can you explain your a) and b) please? I still do not see it
$endgroup$
– user61049
Feb 5 '13 at 15:08
$begingroup$
Can you explain your a) and b) please? I still do not see it
$endgroup$
– user61049
Feb 5 '13 at 15:08
$begingroup$
@user61049 in part (a) you will multiply $2500$ with $-7$ and then add $1000$. In part (b) you will multiply the range $7500$ with $7$ and in part (c) you will multiply the standard deviation $5500$ with $7$ and then take the square of it. Tell me the unclear parts if there are and then i think about another way of explanation.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 18:44
$begingroup$
@user61049 in part (a) you will multiply $2500$ with $-7$ and then add $1000$. In part (b) you will multiply the range $7500$ with $7$ and in part (c) you will multiply the standard deviation $5500$ with $7$ and then take the square of it. Tell me the unclear parts if there are and then i think about another way of explanation.
$endgroup$
– Seyhmus Güngören
Feb 5 '13 at 18:44
add a comment |
Thanks for contributing an answer to Mathematics Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f295283%2fstatistics-question-revenue-cost%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
$begingroup$
I'd like to know how they got those numbers too. I don't mean the numbers in the answers (those are easy), I mean the numbers in the question: the mean, range, and sample standard deviation of cost. I do not see how the values given for those three numbers can possibly occur together.
$endgroup$
– David K
Oct 13 '15 at 5:19