The level of significance in hypothesis testing is the proba

The level of significance in hypothesis testing is the probability of

Select one:

A. accepting a true null hypothesis

B. accepting a false null hypothesis

C. rejecting a true null hypothesis

D. None of these alternatives is correct.

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A sample of 81 account balances of a credit company showed an average balance of $1,200 with a standard deviation of $126. You want to determine if the mean of all account balances is significantly different from $1,150. Use a .05 level of significance.

Select one:

A. Z = 2.57; therefore, reject H₀

B. Z = 3.57; therefore, reject H₀

C. Z = 4.57; therefore, reject H₀

D. Z = 1.57; therefore, fail to reject H₀

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To construct an interval estimate for the difference between the means of two populations which are normally distributed and have equal variances, we must use a t distribution with (let n₁ be the size of sample 1 and n₂ the size of sample 2)

Select one:

A. (n₁ + n₂) degrees of freedom

B. (n₁ + n₂ - 1) degrees of freedom

C. (n₁ + n₂ - 2) degrees of freedom

D. n₁ - n₂ + 2

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A two-tailed test is performed at 95% confidence. The p-value is determined to be 0.09. The null hypothesis

Select one:

A. must be rejected

B. should not be rejected

C. could be rejected, depending on the sample size

D. has been designed incorrectly

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Allied Corporation is trying to sell its new machines to Ajax. Allied claims that the machine will pay for itself since the time it takes to produce the product using the new machine is significantly less than the production time using the old machine. To test the claim, independent random samples were taken from both machines. You are given the following results.

Use a .05 level of significance. As the statistical advisor to Ajax, would you recommend purchasing Allied\'s machine if the value of the test statistic 2.222?

Select one:

A. Ajax should purchase Allied\'s machine since the null hypothesis was rejected.

B. Ajax should not purchase Allied\'s machine since the null hypothesis was not rejected.

C. Ajax should not purchase Allied\'s machine since the null hypothesis was rejected.

D. Ajax should purchase Allied\'s machine since the null hypothesis was not rejected.

E. None of the above answers is correct

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Independent random samples taken at two local malls provided the following information regarding purchases by patrons of the two malls.

At 95% confidence, test to determine whether or not there is a significant difference between the average purchases by the patrons of the two malls. Determine the value of the test statistic.

Select one:

A. Z = 2.65

B. t = 2.65

C. Z = -2.79

D. Z = 2.45

E. None of the above answers is correct

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A school administrator believes that there is no difference in the student dropout rate for schools located in his district and schools located in another district. A random sample of 25 schools in the administrator\'s district was taken. The student dropout rate of the schools in the sample was 24%. A random sample of 30 schools in the other district had a dropout rate of 27%. Give a point estimate of the standard deviation for the difference between the population proportions for the two districts.

Select one:

A. 0.0128

B. 0.0532

C. 0.0871

D. 0.1178

E. None of the above answers is correct

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The management of Recover Fast Hospital (RFH) claims that the average length of stay in their hospital after a major surgery is less than the average length of stay at General Hospital (GH). The following data has been accumulated to test their claim. Assume the two populations are normally distributed and have equal variances.

Select one:

A. t = -4.716

B. Z = -4.716

C. t = -3.123

D. Z = 3.123

E. None of the above answers is correct

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Recently, a local newspaper reported that part-time students are older than full time students. In order to test the validity of its statement, two independent samples of students were selected. The following shows the ages of the students in the two samples. Using the following data, test to determine whether or not the average age of part time students is significantly more than full-time students. Use an Alpha of 0.05. Assume the populations are normally distributed and have equal variances.

If the value of the t statistic is 0.8, what conclusion should be drawn?

Select one:

A. Reject null hypothesis, average age of part time students is significatly higher than full-time students

B. Fail to reject null hypothesis, average age of part time students is significatly higher than full-time students

C. Fail to reject null hypothesis, average age of part time students is not significatly higher than full-time students

D. Reject null hypothesis, average age of part time students is significatly lower than full-time students

E. Reject null hypothesis, average age of part time students is significatly different than full-time students

F. None of the above answers is correct

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For a one-tailed test (lower tail) at 93.7% confidence, Z =

Select one:

A. -1.86

B. -1.53

C. -1.96

D. -1.645

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An estimate of the variance of a population based on the combination of two sample results is known as the

Select one:

A. pooled standard deviation

B. matched variance

C. pooled variance estimate

D. None of these alternatives is correct.

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In hypothesis testing if the null hypothesis has been rejected when the alternative hypothesis has been true,

Select one:

A. a Type I error has been committed

B. a Type II error has been committed

C. either a Type I or Type II error has been committed

D. the correct decision has been made

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The reliability of two types of machines used in the same manufacturing process is to be tested. The first machine failed to operate correctly in 45 out of 300 trials while the second type failed to operate correctly in 50 out of 250 trials. Calculate the standard deviation of the sampling distribution for the difference between the sample proportions.

Select one:

A. 0.0012

B. 0.0326

C. 0.1727

D. 0.134

E. None of the above answers is correct

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a.) At 95% confidence, test the above hypothesis. What is(are) the critical value(s) of the test statistic?

Select one:

A. -1.645

B. 1.645

C. 1.96

D. -1.96

E. -1.96 and 1.96

F. None of the above answers is correct

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Allied Corporation is trying to determine whether to purchase Machine A or B. It has leased the two machines for a month. A random sample of 5 employees has been taken. These employees have gone through a training session on both machines. Below you are given information on their productivity rate on both machines. (Let the difference \"d\" be d = A - B.)

If the value of the test statistic is equal to -2.17 and the objective of the test of hypothesis is to determine whether the two machines are different at significance level of 10%, what conclusion should be drawn?

Select one:

A. Reject null hypothesis, the two machines are different

B. Reject null hypothesis, the two machines are not different

C. Fail to reject null hypothesis, the two machines are different

D. Fail to reject null hypothesis, the two machines are not different

E. None of the above answers is correct

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Exhibit 9-4
The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes with a standard deviation of 0.5 minutes. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes.
Refer to Exhibit 9-4. The p-value is

Select one:

A. 0.025

B. 0.0456

C. 0.05

D. 0.0228

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A random sample of 100 people was taken. Eighty of the people in the sample favored Candidate A. We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly more than 75%. The p-value is

Select one:

A. 0.2112

B. 0.05

C. 0.025

D. 0.1251

Question 18

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It is said that more males register to vote in a national election than females. A research organization selected a random sample of 300 registered voters and reported that 165 of the registered voters were male. Based on the sample results, can you conclude that more males registered to vote than females? Use a 0.05 level of significance. State the null and alternative hypotheses.

Select one:

D. None of the above answers is correct

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Select one:

D. None of the above answers is correct

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It is believed that people who live in northern Illinois are less likely to return sweepstakes entries than people who live in southern Illinois. Three hundred sweepstakes entries were sent to people in northern Illinois, and 300 entries were sent to people in southern Illinois. Fifty-four percent of the people in northern Illinois return the entries, and 50% of the people in southern Illinois returned the entries. Give a point estimate for the standard deviation of the difference between the population proportions for the two regions.

Select one:

A. 0.0108

B. 0.0208

C. 0.0308

D. 0.0408

E. None of the above answers is correct

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The average life expectancy of tires produced by the Whitney Tire Company has been 40,000 miles. Management believes that due to a new production process, the life expectancy of their tires has increased. In order to test the validity of their belief, the correct set of hypotheses is

Select one:

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Exhibit 9-3

Refer to Exhibit 9-3. If the test is done at the 5% level of significance, the null hypothesis should

Select one:

A. not be rejected

B. be rejected

C. Not enough information given to answer this question.

D. None of these alternatives is correct.

Question 23

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To compute an interval estimate for the difference between the means of two populations, the t distribution

Select one:

A. is restricted to small sample situations when population variance is unknown

B. is not restricted to small sample situations if the population variance is known

C. can be applied when the populations have equal means

D. None of these alternatives is correct.

Question 24

If a hypothesis test leads to the rejection of the null hypothesis

Select one:

A. a Type II error must have been committed

B. a Type II error may have been committed

C. a Type I error must have been committed

D. a Type I error may have been committed

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A student claims that the average grade on the final examination in statistics is going to be at least 85. Another student plans on taking a sample to test the other student\'s claim. The correct set of hypotheses is

Select one:

	New Machine	Old Machine
Sample Mean	25	23
Sample Variance	27	7.56
Sample Size	45	36

Solution

Q2.

Set Up Hypothesis
Null Hypothesis H0: U=1150
Alternate Hypothesis H1: U!=1150
Test Statistic
Population Mean(U)=1150
Given That X(Mean)=1200
Standard Deviation(S.D)=126
Number (n)=81
we use Test Statistic (Z) = x-U/(s.d/Sqrt(n))
Zo=1200-1150/(126/Sqrt(81)
Zo =3.5714
| Zo | =3.5714
Critical Value
The Value of |Z | at LOS 0.05% is 1.96
We got |Zo| =3.5714 & | Z | =1.96
Make Decision
Hence Value of | Zo | > | Z | and Here we Reject Ho
P-Value : Two Tailed ( double the one tail ) - Ha : ( P != 3.5714 ) = 0.0004
Hence Value of P0.05 > 0.0004, Here we Reject Ho

B. Z = 3.57; therefore, reject H0

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