Question 1

P-value for a two tailed test with a test-statistic of -1.15 from a sample of size 21.

Accepted Answer

A) Less than 0.02 
B) Between 0.02 and 0.05 
C) Between 0.05 and 0.10 
D) Between 0.10 and 0.20 
E) Larger than 0.20 
A) Less than 0.02 
B) Between 0.02 and 0.05 
C) Between 0.05 and 0.10 
D) Between 0.10 and 0.20 
E) Larger than 0.20

Question 2

P-value for t ≥ 2.13 for a sample of size 31

Accepted Answer

A) 0.0520 
B) 0.0207 
C) 0.9793 
D) 0.0087 
E) 0.0347 
A) 0.0520 
B) 0.0207 
C) 0.9793 
D) 0.0087 
E) 0.0347

Question 3

A researcher wants to estimate the mean cholesterol level of people in his city.A random sample of 21 people yields a mean cholesterol level of 224 and a standard deviation of 12.Construct a 95% confidence interval.

Accepted Answer

A) (218.54,229.46) 
B) (214.97,233.03) 
C) (219.69,228.31) 
D) (219.60,228.40) 
E) (223.01,224.99) 
A) (218.54,229.46) 
B) (214.97,233.03) 
C) (219.69,228.31) 
D) (219.60,228.40) 
E) (223.01,224.99)

Question 4

Based on a sample of size 42,a 95% confidence interval for the mean score of all students on an aptitude test is from 57.2 to 64.8.

Accepted Answer

A) 3.8 
B) 0.05 
C) 7.6 
D) 1.15 
E) Not enough information is given. 
A) 3.8 
B) 0.05 
C) 7.6 
D) 1.15 
E) Not enough information is given.

Question 5

P-value for $| t |$ > 1.44 with 45 degrees of freedom

Accepted Answer

A) 0.1568 
B) 0.9215 
C) 0.0808 
D) 0.0785 
E) 0.1916 
A) 0.1568 
B) 0.9215 
C) 0.0808 
D) 0.0785 
E) 0.1916

Question 6

Students investigating the packaging of chocolate chip cookies purchased 10 450-gram bags of a particular brand.They carefully weighed the contents of each bag,recording the following weights (in grams): 467.6,427.9,464.8,447.8,447.8,456.3,459.1,444.9,439.3,450.6.The students plan to test the hypothesis that the mean weight agrees with the company's stated weight on each bag.Decide whether or not the conditions and assumptions for inference with a t-test are satisfied.Explain your answer.

Accepted Answer

The data probably comprise a random samp

Question 7

90% confidence interval with df = 4

Accepted Answer

A) 2.353 
B) 1.645 
C) 4.604 
D) 2.132 
E) 1.533 
A) 2.353 
B) 1.645 
C) 4.604 
D) 2.132 
E) 1.533

Question 8

A manufacturer claims that the mean amount of juice in its $500 \mathrm {~mL}$ bottles is $501.2 \mathrm {~mL} \text {. }$ A consumer advocacy group wants to perform a hypothesis test to determine whether the mean amount is actually less than this.

Accepted Answer

A) Two-sided 
B) Lower-tailed 
C) Upper-tailed 
A) Two-sided 
B) Lower-tailed 
C) Upper-tailed

Question 9

How tall is your average statistics classmate? To determine this,you measure the height of a random sample of 15 of your 100 fellow students,finding a 95% confidence interval for the mean height of 164.76 to 170.90 cm.

Accepted Answer

A) 1.43 cm 
B) 6.14 cm 
C) 3.07 cm 
D) 2.11 cm 
E) Not enough information is given. 
A) 1.43 cm 
B) 6.14 cm 
C) 3.07 cm 
D) 2.11 cm 
E) Not enough information is given.

Question 10

80% confidence interval with df = 11

Accepted Answer

A) 1.280 
B) 1.372 
C) 2.718 
D) 1.356 
E) 1.363 
A) 1.280 
B) 1.372 
C) 2.718 
D) 1.356 
E) 1.363

Question 11

P-value for a left tailed test with a test-statistic of -1.85 from a sample of size 61.

Accepted Answer

A) Less than 0.005 
B) Between 0.005 and 0.01 
C) Between 0.01 and 0.025 
D) Between 0.025 and 0.05 
E) Larger than 0.05 
A) Less than 0.005 
B) Between 0.005 and 0.01 
C) Between 0.01 and 0.025 
D) Between 0.025 and 0.05 
E) Larger than 0.05

Question 12

P-value for t ≤ 1.76 with 24 degrees of freedom

Accepted Answer

A) 0.9772 
B) 0.0228 
C) 0.9544 
D) 0.9088 
E) 0.0456 
A) 0.9772 
B) 0.0228 
C) 0.9544 
D) 0.9088 
E) 0.0456

Question 13

How much fat do reduced fat cookies typically have? You take a random sample of 51 reduced-fat cookies and test them in a lab,constructing the following confidence interval: t-Interval for μ: with 90.00% Confidence,
2.3 < μ(grams of fat)< 3.4

Accepted Answer

A) 0.55 grams of fat 
B) 2.85 grams of fat 
C) 1.48 grams of fat 
D) 1.10 grams of fat 
E) Not enough information is given. 
A) 0.55 grams of fat 
B) 2.85 grams of fat 
C) 1.48 grams of fat 
D) 1.10 grams of fat 
E) Not enough information is given.

Question 14

A bank needs information concerning the checking account balances of its local customers.A random sample of 14 accounts was checked and yielded a mean balance of $664.14 and a standard deviation of $297.29.Find a 98% confidence interval for the true mean checking account balance for local customers.

Accepted Answer

A) ($492.52,$835.76) 
B) ($493.71,$834.57) 
C) ($455.65,$872.63) 
D) ($453.56,$874.72) 
E) ($455.65,$835.76) 
A) ($492.52,$835.76) 
B) ($493.71,$834.57) 
C) ($455.65,$872.63) 
D) ($453.56,$874.72) 
E) ($455.65,$835.76)

Question 15

In the past,the mean battery life for a certain type of flashlight battery has been $8.8 \text { hours. }$ The manufacturer has introduced a change in the production method and wants to perform a hypothesis test to determine whether the mean battery life has increased as a result.The hypotheses are: H0 : ? = 8.8 hours
HA : ? > 8.8 hours
Explain the result of a Type I error.

Accepted Answer

A) The manufacturer will decide the mean battery life is 8.8 hours when in fact it is greater than 8.8 hours. 
B) The manufacturer will decide the mean battery life is 9.6 hours greater than it was prior to the change in the production method. 
C) The manufacturer will decide the mean battery life is 9.6 hours lower than it was prior to the change in the production method. 
D) The manufacturer will decide the mean battery life is greater than 8.8 hours when in fact it is greater than 8.8 hours. 
E) The manufacturer will decide the mean battery life is greater than 8.8 hours when in fact it is 8.8 hours. 
A) The manufacturer will decide the mean battery life is 8.8 hours when in fact it is greater than 8.8 hours. 
B) The manufacturer will decide the mean battery life is 9.6 hours greater than it was prior to the change in the production method. 
C) The manufacturer will decide the mean battery life is 9.6 hours lower than it was prior to the change in the production method. 
D) The manufacturer will decide the mean battery life is greater than 8.8 hours when in fact it is greater than 8.8 hours. 
E) The manufacturer will decide the mean battery life is greater than 8.8 hours when in fact it is 8.8 hours.

Question 16

A sample of 51 statistics students at a large university had a mean final exam score of 76 with a standard deviation of 4.Find a 95% confidence interval for the mean final exam score for all statistics students at this university.

Accepted Answer

A) (75.6,76.1) 
B) (75.6,76.4) 
C) (79.4,82.6) 
D) (74.9,77.1) 
E) (75.9,76.1) 
A) (75.6,76.1) 
B) (75.6,76.4) 
C) (79.4,82.6) 
D) (74.9,77.1) 
E) (75.9,76.1)

Question 17

A 99% confidence interval from a sample of size 41

Accepted Answer

A) 2.423 
B) 2.576 
C) 2.690 
D) 2.725 
E) 2.704 
A) 2.423 
B) 2.576 
C) 2.690 
D) 2.725 
E) 2.704

Question 18

P-value for a two tailed test with a test-statistic of 2.95 from a sample of size 23.

Accepted Answer

A) Less than 0.01 
B) Between 0.01 and 0.02 
C) Between 0.02 and 0.05 
D) Between 0.05 and 0.10 
E) Larger than 0.10 
A) Less than 0.01 
B) Between 0.01 and 0.02 
C) Between 0.02 and 0.05 
D) Between 0.05 and 0.10 
E) Larger than 0.10

Question 19

Analysis of a random sample of 250 Nova Scotia nurses produced a 95% confidence interval for the mean annual salary of $$\$ 42,807 < \mu \text { (Nurse Salary) } < \$ 49,699 \text {. }$$

Accepted Answer

A) About 95% of Nova Scotia nurses earn between $42,807 and $49,699. 
B) We are 95% confident that the average nurse salary in the Canada is between $42,807 and $49,699. 
C) About 95% of the nurses surveyed earn between $42,807 and $49,699. 
D) We are 95% confident that the interval from $42,807 to $49,699 contains the true mean salary of all Nova Scotia nurses. 
E) If we took many random samples of Nova Scotia nurses,about 95% of them would produce this confidence interval. 
A) About 95% of Nova Scotia nurses earn between $42,807 and $49,699. 
B) We are 95% confident that the average nurse salary in the Canada is between $42,807 and $49,699. 
C) About 95% of the nurses surveyed earn between $42,807 and $49,699. 
D) We are 95% confident that the interval from $42,807 to $49,699 contains the true mean salary of all Nova Scotia nurses. 
E) If we took many random samples of Nova Scotia nurses,about 95% of them would produce this confidence interval.

Question 20

How much fat do reduced-fat cookies typically have? You take a random sample of 51 reduced-fat cookies and test them in a lab,constructing the following confidence interval: t-Interval for μ: with 90.00% Confidence,
2.3 < μ(grams of fat)< 3.4

Accepted Answer

A) 0.33 
B) 0.55 
C) 0.66 
D) 3.05 
E) Not enough information is given. 
A) 0.33 
B) 0.55 
C) 0.66 
D) 3.05 
E) Not enough information is given.

Exam 20: Inferences About Means

P-value for a two tailed test with a test-statistic of -1.15 from a sample of size 21.

P-value for t ≥ 2.13 for a sample of size 31

A researcher wants to estimate the mean cholesterol level of people in his city.A random sample of 21 people yields a mean cholesterol level of 224 and a standard deviation of 12.Construct a 95% confidence interval.

Based on a sample of size 42,a 95% confidence interval for the mean score of all students on an aptitude test is from 57.2 to 64.8.

P-value for ∣t∣| t |∣t∣ > 1.44 with 45 degrees of freedom

90% confidence interval with df = 4

A manufacturer claims that the mean amount of juice in its 500 mL500 \mathrm {~mL}500 mL bottles is 501.2 mL. 501.2 \mathrm {~mL} \text {. }501.2 mL. A consumer advocacy group wants to perform a hypothesis test to determine whether the mean amount is actually less than this.

How tall is your average statistics classmate? To determine this,you measure the height of a random sample of 15 of your 100 fellow students,finding a 95% confidence interval for the mean height of 164.76 to 170.90 cm.

80% confidence interval with df = 11

P-value for a left tailed test with a test-statistic of -1.85 from a sample of size 61.

P-value for t ≤ 1.76 with 24 degrees of freedom

How much fat do reduced fat cookies typically have? You take a random sample of 51 reduced-fat cookies and test them in a lab,constructing the following confidence interval: t-Interval for μ: with 90.00% Confidence, 2.3 < μ(grams of fat)< 3.4

A sample of 51 statistics students at a large university had a mean final exam score of 76 with a standard deviation of 4.Find a 95% confidence interval for the mean final exam score for all statistics students at this university.

A 99% confidence interval from a sample of size 41

P-value for a two tailed test with a test-statistic of 2.95 from a sample of size 23.

Analysis of a random sample of 250 Nova Scotia nurses produced a 95% confidence interval for the mean annual salary of $42,807<μ (Nurse Salary) <$49,699. \$ 42,807 < \mu \text { (Nurse Salary) } < \$ 49,699 \text {. }$42,807<μ (Nurse Salary) <$49,699.

How much fat do reduced-fat cookies typically have? You take a random sample of 51 reduced-fat cookies and test them in a lab,constructing the following confidence interval: t-Interval for μ: with 90.00% Confidence, 2.3 < μ(grams of fat)< 3.4

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P-value for $| t |$ > 1.44 with 45 degrees of freedom

A manufacturer claims that the mean amount of juice in its $500 \mathrm {~mL}$ bottles is $501.2 \mathrm {~mL} \text {. }$ A consumer advocacy group wants to perform a hypothesis test to determine whether the mean amount is actually less than this.

Analysis of a random sample of 250 Nova Scotia nurses produced a 95% confidence interval for the mean annual salary of $\$ 42,807 < \mu \text { (Nurse Salary) } < \$ 49,699 \text {. }$