BUSI 230 HW 9.3 Hypothesis Tests for a Population Mean, Standard Deviation Unknown Assignment solutions complete answers
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Select the appropriate word or phrase to complete the sentence.
The number of degrees of freedom for the Student's t-test of a population mean is always less than the .
What is the relationship between confidence intervals and hypothesis testing?
When testing versus , if a confidence interval does not contain , we at the level.
If we decrease the value of the significance level , we the probability of a Type I error.
If we decrease the value of the significance level , we the probability of a Type II error.
Is there a doctor in the house? A market research firm reported the mean annual earnings of all family practitioners in the United States was $178,258. A random sample of 57 family practitioners in Los Angeles had mean earnings of x=$192,890 with a standard deviation of $43,107. Do the data provide sufficient evidence to conclude that the mean salary for family practitioners in Los Angeles differs from the national average? Use the =0.10 level of significance and the P-value method with the TI-84 calculator.
(a) State the appropriate null and alternate hypotheses.
(b) Compute the value of the test statistic. Round the answer to two decimal places.
(c) Compute the P-value. Round the answer to four decimal places.
(d) Determine whether to reject H0.
(e) State a conclusion.
College tuition: The mean annual tuition and fees for a sample of 24 private colleges in California was $37,000 with a standard deviation of $7,800. A dotplot shows that it is reasonable to assume that the population is approximately normal. Can you conclude that the mean tuition and fees for private institutions in California is greater than $35,000? Use the =0.10 level of significance and the P-value method with the TI-84 Plus calculator.
(a) State the appropriate null and alternate hypotheses.
(b) Compute the value of the test statistic. Round the answer to two decimal places.
(c) Compute the -value. Round the -value to at least four decimal places.
(d) Determine whether to reject .
(e) State a conclusion.
Commuting to work: A community survey sampled 1923 people in Colorado and asked them how long it took them to commute to work each day. The sample mean one-way commute time was 24.6 minutes with a standard deviation of 13 minutes. A transportation engineer claims that the mean commute time is less than 25 minutes. Do the data provide convincing evidence that the engineer's claim is true? Use the =0.10 level of significance and the P-value method with the TI-84 Plus calculator.
(a) State the appropriate null and alternate hypotheses.
This hypothesis test is a
(b) Compute the value of the test statistic. Round the answer to two decimal places.
(c) Compute the -value. Round the answer to at least four decimal places.
(d) Determine whether to reject .
(e) State a conclusion.
