Chapter 8 day 1

# Chapter 8 day 1

## Chapter 8 day 1

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##### Presentation Transcript

1. Chapter 8 day 1 BELL RINGER!

2. Bell Ringer 50: When you are put on trial for a crime, as you enter the court room are you innocent or guilty?

3. Chapter 8 day 2 BELL RINGER!

4. Bell Ringer 51: A researcher reports that the average salary of assistant professors is more than \$42,000. A sample of 30 assistant professors has a mean salary of \$43,260. At α = 0.05, test the claim given that the standard deviation of the population is \$5230. State the null and alternative hypotheses.

5. Chapter 8 day 3 BELL RINGER!

6. Bell Ringer 52: A researcher reports that the average salary of assistant professors is more than \$42,000. A sample of 30 assistant professors has a mean salary of \$43,260. At α = 0.05, test the claim given that the standard deviation of the population is \$5230. Find the critical value and draw the appropriate figure showing the critical region.

7. Chapter 8 day 4 BELL RINGER!

8. Bell Ringer 53: At a certain university the mean income of parents of the entering class is reported to be \$91,600. The president of another university feels that the parents’ income for her entering class is greater than \$91,600. She surveys 100 randomly selected families and finds the mean income to be \$96,321 with a standard deviation of \$9555. With α = 0.05, is she correct?

9. Chapter 8 day 5 BELL RINGER!

10. Bell Ringer 54: One of your distributors reports an average of 150 sales per day. You suspect that this average is not accurate, so you randomly select 35 days and determine the number of sales each day. Your data provides a mean of 143 daily sales with a standard deviation of 15 sales. At α = 0.01, is there enough evidence to doubt the distributor’s reported average?

11. Chapter 8 day 6 BELL RINGER!

12. Bell Ringer 55: State the null and alternative hypotheses then find the critical t-value of the following scenario: A job placement director claims that the average starting salary for nurses is \$24,000. A sample of 10 nurses has a mean of \$23,450 and a standard deviation of \$400. Is there enough evidence to reject the director’s claim at α = 0.05?

13. Chapter 8 day 7 BELL RINGER!

14. Bell Ringer 56: The average running time for current Broadway shows is 2 hours and 12 minutes. A producer in another city claims that the length of time of productions in his city is the same. He samples 8 shows and finds the time to be 2 hours and 5 minutes with a standard deviation of 11 minutes. Using α = 0.05, is the producer correct?

15. Chapter 8 day 8 BELL RINGER!

16. Bell Ringer 57: A recent survey indicated that the average amount spent for breakfast by business managers was \$7.58 with a standard deviation of \$0.42. It was felt that breakfasts on the West Coast were higher than \$7.58. A sample of 81 business managers on the West Coast had an average breakfast cost of \$7.65. Test this claim using α= 0.03.

17. Chapter 8 day 9 BELL RINGER!

18. Bell Ringer 58: An attorney claims that more than 25% of all lawyers advertise. A sample of 200 lawyers in a certain city showed that 63 had used some form of advertising. At α = 0.05, is there enough evidence to support the attorney’s claim?

19. Chapter 8 day 10 BELL RINGER!

20. Bell Ringer 59: A credit card company wondered whether giving frequent flyer miles for every purchase would increase card usage, which has a current mean of \$2500 per year. They gave free miles to a random sample of 30 credit card customers and found the sample mean to be \$2542. Assume the standard deviation is \$109. Use α = 0.05 to test the claim.