1. IA Credit Card Company wants to evaluate the usage of their card. They randomly selected 16 credit card holders and found that the mean amount they charged in the past twelve months was $2017, while the standard deviation was $867. Use a 0.025 significance level to evaluate the claim that the mean amount charged by all credit card holders was greater than $1750.
A. State the null and alternate hypotheses.
B. State the decision rule.
C. Compute the value of the test statistic.
D. What is your decision regarding the null hypotheses?
2. A retail management trade journal reported that the typical shopper spends an average of 1.80 hours per visit in shopping mall. A sample of 8 shoppers at theByrnswick Mall in south Toledo revealed the following times. At the 0.01 significance level, can we conclude that shoppers at the Byrnwick Mall spend less than a mean of 1.80 hours?
1.6 1.5 1.6 2.1 1.5 1.9 1.8 2.0
A. State the null and alternate hypotheses.
B. State the decision rule.
C. Compute the value of the test statistic.
D. What is the decision regarding the null hypothesis?
3. The mean construction time for a standard two-car garage by Arrowhead Construction Company is 3.5 days. The time for the construction process follows the normal distribution. The construction process is modified through the use of a "quick setting concrete" for the foundation and floor. This should allow the next phase of construction to start in a more timely manner. A sample of 12 garages had a mean construction time of 3 days with a standard deviation of 0.9 days. Does use of the quick setting concrete decrease construction time?
A. State the null and alternate hypotheses:
B. State the decision rule:
C. Compute the value of the test statistic.
D. What is your decision regarding the null hypothesis?
4. For each of the following statements, give the null hypothesis, Ho, and the alternate Hi. The hi stands for the h with line one or some symbol on the side I did not no how to put it on word.
A. The mean pulse of lawyers is 90.
B. The mean salary of college presidents is at least $162,500.
C. The mean IQ score of 20 years olds is more than 100.
D. The mean annual income of sales associates is less than $38,000.
5. A recent article in a computer magazine suggested that the mean time to fully learn a new software program is 40 hours. A sample of 100 first-time users of a new software program revealed the mean time to learn it was 39 hours with the standard deviation of 8 hours. At the .05 significance level, can we conclude that users learn the package in less than a mean of 40 hours?
A. State the null and alternate hypotheses.
B. State the decision rule.
C. Compute the value of the test statistic.
D. What is your decision regarding the null hypothesis? Interpret the result.