# A lab technician is tested for her consistency by taking multiple

Question 1 of 20 1.0 Points

A lab technician is tested for her consistency by taking multiple measurements of cholesterol levels from the same blood sample. The target accuracy is a variance in measurements of 1.2 or less. If the lab technician takes 16 measurements and the variance of the measurements in the sample is 2.2, does this provide enough evidence to reject the claim that the lab technician’s accuracy is within the target accuracy?

State the null and alternative hypotheses.

A. H0: s2 ≥ 1.2, H1: s2 ≠ 1.2

B. H0: s2 ≠ 1.2, H1: s2 = 1.2

C. H0: s2 < 1.2, H1: s2 ≠ 1.2

D. H0: s2 ≤ 1.2, H1: s2 > 1.2 Reset Selection

Question 2 of 20 1.0 Points

Smaller p-values indicate more evidence in support of the:

A. alternative hypothesis

B. the reduction of variance

C. quality of the researcher

D. null hypothesis Reset Selection

Question 3 of 20 1.0 Points

The hypothesis that an analyst is trying to prove is called the:

A. quality of the researcher

B. alternative hypothesis

C. level of significance

D. elective hypothesis Reset Selection

Question 4 of 20 1.0 Points

A severe storm has an average peak wave height of 16.4 feet for waves hitting the shore. Suppose that a storm is in progress with a severe storm class rating. Let us say that we want to set up a statistical test to see if the wave action (i.e., height) is dying down or getting worse. If you wanted to test the hypothesis that the waves are dying down, what would you use for the alternate hypothesis? Is the P-value area on the left, right, or on both sides of the mean?

A. H1: is not equal to 16.4 feet; the P-value area is on the right of the mean

B. H1: is greater than 16.4 feet; the P-value area is on the left of the mean

C. H1: is greater than 16.4 feet; the P-value area is on both sides of the mean

D. H1: is less than 16.4 feet; the P-value area is on the left of the mean Reset Selection

Question 5 of 20 1.0 Points

A manufacturer of flashlight batteries took a sample of 13 batteries from a day’s production and used them continuously until they failed to work. The life lengths of the batteries, in hours, until they failed were: 342, 426, 317, 545, 264, 451, 1049, 631, 512, 266, 492, 562, and 298.

At the .05 level of significance, is there evidence to suggest that the mean life length of the batteries produced by this manufacturer is more than 400 hours?

A. No, because the p-value for this test is equal to .1164

B. Yes, because the test value 1.257 is less than the critical value 2.179

C. No, because the test value 1.257 is greater than the critical value 1.115

D. Yes, because the test value 1.257 is less than the critical value 1.782 Reset Selection

Question 6 of 20 1.0 Points

Results from previous studies showed 79% of all high school seniors from a certain city plan to attend college after graduation. A random sample of 200 high school seniors from this city reveals that 162 plan to attend college. Does this indicate that the percentage has increased from that of previous studies? Test at the 5% level of significance.

What is your conclusion?

A. Cannot determine

B. More seniors are going to college

C. Reject H0. There is enough evidence to support the claim that the proportion of students planning to go to college is now greater than .79.

D. Do not reject H0. There is not enough evidence to support the claim that the proportion of students planning to go to college is greater than .79. Reset Selection

Question 7 of 20 1.0 Points

In an article appearing in Today’s Health a writer states that the average number of calories in a serving of popcorn is 75. To determine if the average number of calories in a serving of popcorn is different from 75, a nutritionist selected a random sample of 20 servings of popcorn and computed the sample mean number of calories per serving to be 78 with a sample standard deviation of 7.

State the null and alternative hypotheses.

A. H0: 75, H1: < 75

B. H0: = 75, H1: > 75

C. H0: = 75, H1: ≠ 75

D. H0: 75, H1: > 75 Reset Selection

Question 8 of 20 1.0 Points

A type I error occurs when the:

A. null hypothesis is incorrectly rejected when it is true

B. sample mean differs from the population mean

C. null hypothesis is incorrectly accepted when it is false

D. test is biased Reset Selection

Question 9 of 20 1.0 Points

The form of the alternative hypothesis can be:

A. neither one nor two-tailed

B. one-tailed

C. one or two-tailed

D. two-tailed Reset Selection

Question 10 of 20 1.0 Points

A lab technician is tested for her consistency by taking multiple measurements of cholesterol levels from the same blood sample. The target accuracy is a variance in measurements of 1.2 or less. If the lab technician takes 16 measurements and the variance of the measurements in the sample is 2.2, does this provide enough evidence to reject the claim that the lab technician’s accuracy is within the target accuracy?

At the a = .01 level of significance, what is your conclusion?

A.

Reject H0. At the = .01 level of significance, there is not enough evidence to support the claim that this technician’s true variance is larger than the target accuracy.

B. Do not reject H0. At the = .01 level of significance there is not sufficient evidence to suggest that this technician’s true variance is greater than the target accuracy.

C. Cannot determine

D. Reject H0. At the = .01 level of significance, there is enough evidence to support the claim that this technician’s variance is larger than the target accuracy. Reset Selection

Question 11 of 20 1.0 Points

The null and alternative hypotheses divide all possibilities into:

A. two sets that overlap

B. two sets that may or may not overlap

C. as many sets as necessary to cover all possibilities

D. two non-overlapping sets Reset Selection

Part 2 of 3 –

Question 12 of 20 1.0 Points

A survey determines that mint chocolate chip is the favorite ice cream flavor of 6% of consumers. An ice cream shop determines that of 240 customers, 18 customers stated their preference for mint chocolate chip.

Find the P-value that would be used to determine if the percentage of customers who prefer mint chocolate chip ice has increased at a 5% level of significance.

P-value: Round your answer to four decimal places as necessary.

Question 13 of 20 1.0 Points

A medical doctor wishes to test the claim that the standard deviation of the systolic blood pressure of deep sea divers is greater than 450. To do so, she selected a random sample of 25 divers and found s = 468.

Assuming that the systolic blood pressures of deep sea divers are normally distributed, the doctor would perform a chi-square test to test her research hypothesis. In that case, what is the test value that she would compute.

Place your answer, rounded to 3 decimal places, in the blank. For example, 34.567 would be a legitimate entry.

Question 14 of 20 1.0 Points

The ABC battery company claims that their batteries last at least 100 hours, on average. Your experience with their batteries has been somewhat different, so you decide to conduct a test to see if the company’s claim is true. You believe that the mean life is actually less than the 100 hours the company claims. You decide to collect data on the average battery life (in hours) of a random sample of n = 20 batteries. Some of the information related to the hypothesis test is presented below.

Test of H0: 100 versus H1: 100

Sample mean 98.5

Std error of mean 0.777

Assuming the life length of batteries is normally distributed, if you wish to conduct this test using a .05 level of significance, what is the critical value that you should use? Place your answer, rounded to 3 decimal places in the blank. For example, -1.234 would be a legitimate entry.

Question 15 of 20 1.0 Points

At a university, the average cost of books per student has been $550 per student per semester. The Dean of Students believes that the costs are increasing and that the average is now greater than $550. He surveys a sample of 40 students and finds that for the most recent semester their average cost was $630 with a standard deviation of $120. What is the test value for this hypothesis test?

Test value: Round your answer to two decimal places as necessary.

Question 16 of 20 1.0 Points

A firm that produces light bulbs claims that their lightbulbs last 1500 hours, on average. You wonder if the average might differ from the 1500 hours that the firm claims. To explore this possibility you take a random sample of n = 25 light bulbs purchased from this firm and record the lifetime (in hours) of each bulb. You then conduct an appopriate test of hypothesis. Some of the information related to the hypothesis test is presented below.

Test of H0: = 1500 versus H1: 1500

Sample mean 1509.5

Std error of mean 4.854

Assuming the life length of this type of lightbulb is normally distributed, what is the p-value associated with this test? Place your answer, rounded to 3 decimal places, in the blank. For example, 0.234 would be a legitimate entry.

Question 17 of 20 1.0 Points

Suppose a firm that produces light bulbs wants to know whether it can say that its light bulbs typically last more than 1500 hours. Hoping to find support for their claim, the firm collects a random sample of n = 25 light bulbs and records the lifetime (in hours) of each bulb. The information related to the hypothesis test is presented below.

Test of H0: 1500 versus H1: > 1500

Sample mean 1509.5

Std error of mean 4.854

Assuming the life length of this type of lightbulb is normally distributed, if you wish to conduct this test using a .05 level of significance, what is the critical value that you should use? Place your answer, rounded to 3 decimal places in the blank. For example, 1.234 would be a legitimate entry.

Part 3 of 3 –

Question 18 of 20 1.0 Points

The p-value of a test is the smallest level of significance at which the null hypothesis can be rejected.

True

False

Reset Selection

Question 19 of 20 1.0 Points

The probability of making a Type I error and the level of significance are the same.

True

False

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Question 20 of 20 1.0 Points

Using the confidence interval when conducting a two-tailed test for the population mean, we do not reject the null hypothesis if the hypothesized value for falls between the lower and upper confidence limits.

True

False

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