Cigarette Smoking A researcher found that a cigarette smoker smokes on average 31 cigarettes a day. She feels that this average is too high. She selected a random sample of 10 smokers and found that the mean number of cigarettes they smoked per day was 28. The sample standard deviation was 2.7. At a = 0.05, is there enough evidence to support her claim? Assume that the population is approximately normally distributed. Use the critical value method and tables. Part: 0 / 5 Part 1 of 5 (a) State the hypotheses and identify the claim. (Choose one) ▼ (Choose one) ▼ This hypothesis test is a (Choose one) ▼ test.

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
18th Edition
ISBN:9780079039897
Author:Carter
Publisher:Carter
Chapter10: Statistics
Section10.5: Comparing Sets Of Data
Problem 13PPS
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Sample Question
Cigarette Smoking A researcher found that a cigarette
smoker smokes on average 32 cigarettes a day. She feels
that this average is too high. She selected a random sample
of 9 smokers and found that the mean number of cigarettes
they smoked per day was 29. The sample standard deviation
was 2.9. At a-0.01, is there enough evidence to support her
claim? Assume that the population is approximately
normally distributed. Use the critical value method and
tables.
(2) State the hypotheses and identify the claim.
(b) Find the critical value.
(e) Compute the test value.
(d) Make the decision.
(e) Summarize the results.
Explanation
(a) State the hypotheses and identify the claim.
The null hypothesis n, is the statement that there is no
difference between a parameter and a specific value. This is
equivalent to H:- 32 cigarettes.
The alternative hypothesis I, is the statement that there is
a difference between a parameter and a specific value. In
this case, the mean number of cigarettes smoked per day is
less than 32. This is equivalent to il, :<32 cigarettes.
The problem asks, "Is the mean number of cigarettes
smoked per day less than 32;"
Hence, the claim is the alternative hypothesis.
(b) Find the critical value.
From OThe t Distribution Table, for a left-tailed test with a- 0.01 and
d.f. -9-1-8, the critical value is --2.896.
TABLE F The Distribution
Confidence
intervals
One tail, al
80%
90%
95%
98%
99%
d.f.
0.10
0.05
0.025
0.01
0.005
Two tails
0,20
0,10
0.05
0.02
0.01
1,415
1,895
2.365
2.998
3.499
8
1.397
1.860
2.306
2.896
3.355
9
1.383
1.833
2.262
2.821
3.250
(c) Compute the test value.
The test is a statistical test for the mean of a
population and is used when the population is
normally or approximately normally distributed and
is unknown.
The formula for the test is
The degrees of freedom are d.f. -n-1
Using the formula for the r-test,
29 - 32
2.9//9
--3.103
Hence, the test value, rounded to 3 decimal places, is
I--3.103.
(d) Make the decision.
Since the test value does fall in the critical region, reject the
null hypothesis.
-3.103 -2.896
(e) Summarize the results.
Sinco tho pull bynothocic waC roioctod thoro ic onOugh
Transcribed Image Text:Sample Question Cigarette Smoking A researcher found that a cigarette smoker smokes on average 32 cigarettes a day. She feels that this average is too high. She selected a random sample of 9 smokers and found that the mean number of cigarettes they smoked per day was 29. The sample standard deviation was 2.9. At a-0.01, is there enough evidence to support her claim? Assume that the population is approximately normally distributed. Use the critical value method and tables. (2) State the hypotheses and identify the claim. (b) Find the critical value. (e) Compute the test value. (d) Make the decision. (e) Summarize the results. Explanation (a) State the hypotheses and identify the claim. The null hypothesis n, is the statement that there is no difference between a parameter and a specific value. This is equivalent to H:- 32 cigarettes. The alternative hypothesis I, is the statement that there is a difference between a parameter and a specific value. In this case, the mean number of cigarettes smoked per day is less than 32. This is equivalent to il, :<32 cigarettes. The problem asks, "Is the mean number of cigarettes smoked per day less than 32;" Hence, the claim is the alternative hypothesis. (b) Find the critical value. From OThe t Distribution Table, for a left-tailed test with a- 0.01 and d.f. -9-1-8, the critical value is --2.896. TABLE F The Distribution Confidence intervals One tail, al 80% 90% 95% 98% 99% d.f. 0.10 0.05 0.025 0.01 0.005 Two tails 0,20 0,10 0.05 0.02 0.01 1,415 1,895 2.365 2.998 3.499 8 1.397 1.860 2.306 2.896 3.355 9 1.383 1.833 2.262 2.821 3.250 (c) Compute the test value. The test is a statistical test for the mean of a population and is used when the population is normally or approximately normally distributed and is unknown. The formula for the test is The degrees of freedom are d.f. -n-1 Using the formula for the r-test, 29 - 32 2.9//9 --3.103 Hence, the test value, rounded to 3 decimal places, is I--3.103. (d) Make the decision. Since the test value does fall in the critical region, reject the null hypothesis. -3.103 -2.896 (e) Summarize the results. Sinco tho pull bynothocic waC roioctod thoro ic onOugh
Cigarette Smoking A researcher found that a cigarette smoker smokes on average 31 cigarettes a day. She feels that this
average is too high. She selected a random sample of 10 smokers and found that the mean number of cigarettes they smoked per
day was 28. The sample standard deviation was 2.7. At a = 0.05, is there enough evidence to support her claim? Assume that the
population is approximately normally distributed. Use the critical value method and tables.
Part: 0 /5
Part 1 of 5
(a) State the hypotheses and identify the claim.
Ho
(Choose one) ▼
H
(Choose one) ▼
This hypothesis test is a (Choose one) ▼
test.
Transcribed Image Text:Cigarette Smoking A researcher found that a cigarette smoker smokes on average 31 cigarettes a day. She feels that this average is too high. She selected a random sample of 10 smokers and found that the mean number of cigarettes they smoked per day was 28. The sample standard deviation was 2.7. At a = 0.05, is there enough evidence to support her claim? Assume that the population is approximately normally distributed. Use the critical value method and tables. Part: 0 /5 Part 1 of 5 (a) State the hypotheses and identify the claim. Ho (Choose one) ▼ H (Choose one) ▼ This hypothesis test is a (Choose one) ▼ test.
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