Download Section 9.3 Name___________________________________ 1

Section 9.3
Name___________________________________
1) Match the symbol with the correct definition.
A) The power of a test
B) The probability of a Type I error
C) The probability of failing to reject the null hypothesis when it is true
D) The probability of a Type II error
1)
2-3. The supervisor of a production line believes that the average time to assemble an electronic component is 14 minutes.
Assume that assembly time is normally distributed with a standard deviation of 3.4 minutes. The supervisor times the
assembly of 14 components, and finds that the average time for completion was 11.6 minutes.
2) What are the appropriate null and alternative hypotheses?
A) H0 : µ 14 and Ha: µ > 14
B) H0 : µ = 14 and Ha: µ
C) H0 : µ 14 and Ha: µ < 14
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D) H0 : µ 14 and Ha: µ = 14
3) Which of the following statements is most accurate?
A) Reject the null hypothesis at = 0.025, but not at = 0.05
B) Unable to reject the null hypothesis at
0.10
C) Reject the null hypothesis at = 0.008
D) Reject the null hypothesis at = 0.05, but not at = 0.01
3)
4-5. A pharmaceutical manufacturer is concerned that the mean impurity concentration in pills should not exceed 2%. It is
known that from a particular production run impurity concentrations follow a normal distribution with a standard deviation
0.32%. A random sample of 64 pills from a production run was checked, and the sample mean impurity concentration was
found to be 2.05%.
4) Calculate the p-value for this test.
5) Test at the 5% level the null hypothesis that the population mean impurity concentration is 2% or less against
the alternative that it is more than 2%.
6) T/F. If a researcher is unable to reject the null hypothesis, then the alternative hypothesis should be
accepted.
6)
7-9. The state lottery office claims that the average household income of those people playing the lottery is greater than
$37,000. Assume that the distribution of household income of those people playing the lottery is normally distributed with a
standard deviation of $5,756. Suppose that for a sample of 25 households, it is found that the average income was $36,243.
7) What are the appropriate null and alternative hypotheses?
A) H0 : µ > $37,000 and Ha: µ $37,000
B) H0 : µ = $37,000 and Ha : µ $37,000
7)
8) What is the most accurate estimate of the p-value?
A) p-value < 0.05
B) p-value > 0.10
C) p-value < 0.01
D) p-value < 0.10
8)
9) What is the test statistic for this test?
A) Z = 1.92
B) Z = 0.66
C) Z = 1.12
D) Z = 0.96
C) H0 : µ = $37,000 and Ha: µ > $37,000
D) H0 : µ = $37,000 and Ha: µ < $37,000
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10) If a medical researcher wishes to determine whether there is evidence that the annual mean income
of family physicians in the U.S. is less than $200,000, then which of the following tests should be
utilized?
A) Either a one-sided or two-sided test
B) A one-sided test
C) A two-sided test
D) Cannot be determined from the information
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11) Which of the following does the null hypothesis H0 make a claim about?
11)
12) For a two-tailed test at the 0.05 significance level, what is the rejection region when n is large and
the population standard deviation is known?
A) Smaller than -1.96 or greater than 1.96
B) Smaller than -1.645 or greater than +1.645
C) Between -1.96 and +1.96
D) Between -1.645 and +1.645
12)
13) What is the z-value for a two-sided test of hypothesis for a population mean when the probability
of rejecting a true null hypothesis is equal to .05?
A) 2.330
B) 2.575
C) 1.645
D) 1.960
13)
A) Sample mean
C) Sample statistic
B) Population parameter
D) Sample variance
14-15. A dean of college of business in the Midwest claims that he can correctly identify whether a student is finance major
or a music industry management major by the way the student dresses. Suppose in actuality that he can correctly identify
finance major 84% of the time, while 16% of the time he mistakenly identifies music industry management major as finance
major. Presented with one student and asked to identify the major of this student (who is either a finance or music industry
management major), the dean considers this to be a hypothesis test with the null hypothesis being that the student is a
finance major and the alternative that the student is a music industry management major.
14) Which of the following statements illustrates a Type II error?
A) Saying that the student is music industry management major when in fact the student is
finance major
B) Saying that the student is music industry management major when in fact the student is
music industry management major
C) Saying that the student is finance major when in fact the student is music industry
management major
D) Saying that the student is finance major when in fact the student is finance major
14)
15) Which of the following statements illustrates a Type I error?
A) Saying that the student is music industry management major when in fact the student is
music industry management major
B) Saying that the student is finance major when in fact the student is finance major
C) Saying that the student is music industry management major when in fact the student is
finance major
D) Saying that the student is finance major when in fact the student is music industry
management major
15)
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16) A professor of statistics wants to test that the average amount of money a typical college student
spends per day during spring break is over $70. Based upon previous research, the population
standard deviation is estimated to be $17.32. The professor surveys 35 students and finds that the
mean spending is $72.43. Which of the following statements is most accurate?
A) Reject the null hypothesis at = 0.01
B) Reject the null hypothesis at = 0.05
C) Unable to reject the null hypothesis at
0.10
D) Reject the null hypothesis at = 0.10
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