20 question Statistics quiz

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?
Compute the value of the appropriate test statistic.

A.= 27.50

B.z = 1.65

C. = 30.58

D.t = 27.50

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Question 2 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  = .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.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.

D.Cannot determine

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Question 3 of 20

1.0 Points

Suppose that the mean time for a certain car to go from 0 to 60 miles per hour was 7.7 seconds. Suppose that you want to test the claim that the average time to accelerate from 0 to 60 miles per hour is longer than 7.7 seconds. What would you use for the alternative hypothesis?

A.H1: 7.7 seconds

B.H1:  > 7.7 seconds

C.H1:  = 7.7 seconds

D.H1: < 7.7 seconds Reset Selection Question 4 of 20 1.0 Points A null hypothesis can only be rejected at the 5% significance level if and only if: A.the null hypothesis is biased B.a 95% confidence interval includes the hypothesized value of the parameter C.the null hypotheses includes sampling error D.a 95% confidence interval does not include the hypothesized value of the parameter Reset Selection Question 5 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.More seniors are going to college B.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. C.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. D.Cannot determine Reset Selection Question 6 of 20 1.0 Points A two-tailed test is one where: A.no results lead to the rejection of the null hypothesis B.results in only one direction can lead to rejection of the null hypothesis C.negative sample means lead to rejection of the null hypothesis D.results in either of two directions can lead to rejection of the null hypothesis Reset Selection Question 7 of 20 1.0 Points Which of the following values is not typically used for ? A.0.10 B.0.01 C.0.50 D.0.05 Reset Selection Question 8 of 20 1.0 Points The hypothesis that an analyst is trying to prove is called the: A.level of significance B.alternative hypothesis C.elective hypothesis D.quality of the researcher Reset Selection Question 9 of 20 1.0 Points The alternative hypothesis is also known as the: A.elective hypothesis B.optional hypothesis C.null hypothesis D.research hypothesis Reset Selection Question 10 of 20 1.0 Points The form of the alternative hypothesis can be: A.neither one nor two-tailed B.one or two-tailed C.two-tailed D.one-tailed Reset Selection Question 11 of 20 1.0 Points A type II error occurs when: A.the null hypothesis is incorrectly accepted when it is false B.the sample mean differs from the population mean C.the test is biased D.the null hypothesis is incorrectly rejected when it is true Reset Selection

Part 2 of 3 –

Question 12 of 20

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), “E” or “e” (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where “a” and “b” need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
Let x be a random variable representing dividend yield of Australian bank stocks. We may assume that x has a normal distribution with = 2.8%.  A random sample of 16 Australian bank stocks has a sample mean dividend yield of 8.91%. For the entire Australian stock market, the mean dividend yield is = 6.4%.  If you wanted to test to determine if these data indicate that the dividend yield of all Australian bank stocks is higher than 6.4%, what is the value of the test statistic?  Place your answer, rounded to 3 decimal places, in the blank. For example, 2.345 would be a legitimate entry.

Question 13 of 20

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), “E” or “e” (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where “a” and “b” need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
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 14 of 20

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), “E” or “e” (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where “a” and “b” need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
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, what is the p-value associated with this test? Place your answer, rounded to 3 decimal places in the blank. For example, 0.0234 would be a legitimate entry.

Question 15 of 20

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), “E” or “e” (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where “a” and “b” need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
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 16 of 20

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), “E” or “e” (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where “a” and “b” need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
A survey determines that mint chocolate chip is the favorite ice cream flavor of 6% of consumers. An ice cream shop determines that of 190 customers, 15 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 17 of 20

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), “E” or “e” (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where “a” and “b” need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.
A statistician wishes to test the claim that the standard deviation of the weights of firemen is less than 25 pounds. To do so, she selected a random sample of 20 firemen and found s = 23.2 pounds.
Assuming that the weights of firemen are normally distributed, if the statistician wanted to test her research hypothesis at the .05 level of significance, what is the critical value?
Place your answer, rounded to 3 decimal places, in the blank. For example, 12.345 would be a legitimate entry.

Part 3 of 3 –

Question 18 of 20

1.0 Points

The smaller the p–value, the more evidence there is in favor of the alternative hypothesis.

True

False

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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

A one-tailed alternative is one that is supported by evidence in either direction.

True

False

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