Download College Prep. Stats. Name: Chapter 8 Review Sheet 1. A claim

College Prep. Stats.
Chapter 8 Review Sheet
Name: _____________________________________
1. A claim states that a population mean is less than 100. Is this a right-tailed, left-tailed, or two-tailed test?
2. A claim states that a population mean is equal to 54 when given sample data consisting of x = 56.2, s = 4.79, and n = 37. Will the
critical value be z* or t*?
3. A claim states that a population mean is equal to 54 when given sample data consisting of x = 56.2,  = 4.79, and n = 37. Will the
critical value be z* or t*?
4. A claim states that p = 0.11. Will the test statistic variable be z or t?
5. A researcher claims that 19% of voters favor legalizing marijuana. Assuming that a hypothesis test of the claim has been conducted
and that the conclusion is failure to reject the null hypothesis, state the conclusion in nontechnical terms.
6. If a hypothesis test is conducted using a 0.01 significance level finds the P-value to be 0.015, will you conclude to reject the null
hypothesis or fail to reject the null hypothesis?
7. If a hypothesis test is conducted finds a critical value to be t* = –2.054 and the test statistic to be t = –2.02, will you conclude to
reject the null hypothesis or fail to reject the null hypothesis?
8. If a hypothesis test is conducted finds a critical value to be z* = 1.645 and the test statistic to be z = 1.58, will you conclude to reject
the null hypothesis or fail to reject the null hypothesis?
9. What is the final conclusion obtained when testing the claim that p > 0.25, with a 0.05 significance level, given that the p-value is
0.5555?
10. Identify the null and alternative hypotheses resulting from the claim that the proportion of males is greater than 0.5.
11. A recent study showed that 53% of college applications were submitted online (based on data from the National Association of
College Admissions Counseling). Assume that this result is based on a simple random sample of 900 college applications, with 480
submitted online. Use a 0.01 significance level to test the claim that among all college applications the percentage submitted online is
equal to 50%. Find the critical value.
12. An insurance company is reviewing its current policy rates. When originally setting the rates they believed that the average claim
was $1,800. They are concerned that the true mean is actually higher than this. They randomly select 40 claims, and calculate the
sample mean of $1,950. Assume the standard deviation of claims is $500 and a significance level of .05.
a) Find the critical value.
b) Find the test statistic.
c) Make a conclusion using the information found in parts (a) and (b). (HINT: you do not need to calculate the P-value)
13. A sample of 40 sales receipts from a grocery store has a mean of $137 and a standard deviation of $30.20. Use these values to test
whether or not the mean of sales at the grocery store is less than $150 using a significance level of 0.05.
a) Find the test statistic.
b) Find the P-value.
c) Make a conclusion using the information found in part (b).
14. Use the rejection region below to make a conclusion if the test statistic is –3.727.
15. The TI-83/84 Plus calculator can be used to generate random data from a normally distributed population. The command
randNorm(74,12.5,100) generates 100 values from a normally distributed population with µ = 74 (for pulse rates of women). One
such generated sample of 100 values has x = 74.4 and s = 11.7. Do not make the assumption that the population standard deviation is
known. Use a 0.05 significance level to test the claim that the sample actually does come from a population with a mean equal to 74.
a) State the null and alternative hypothesis.
b) Determine the critical value(s).
c) Calculate the test statistic.
d) Find the P-value.
e) State your conclusion.
16. A supplier of digital memory cards claims that less than 3% of the cards are defective. In a random sample of 600 memory cards,
it is found that 2.8% are defective. At the 0.01 level of significance, test the supplier’s claim that less than 3% are defective.
a) State the null and alternative hypothesis.
b) Determine the critical value(s).
c) Calculate the test statistic.
d) Find the P-value.
e) State your conclusion.
17. The health of employees is monitored by periodically weighing them in. A sample of 54 employees has x = 183.9 lb. Assuming
that  = 97.2 lb, use a 0.10 significance level to test the claim that the population mean of all such employees weights is more than
181.4 lbs.
a) State the null and alternative hypothesis.
b) Determine the critical value(s).
c) Calculate the test statistic.
d) Find the P-value.
e) State your conclusion.
For numbers 18 – 21, use the information provided within each problem to determine if the hypothesis test would involve z*/z
(invNorm/Normalcdf) or t*/t (invT/tcdf).
18. A company claims that the proportion of defective units among a particular model of computers is 4%. In a shipment of 200 such
computers, there are 10 defective units.
19. Various temperature measurements are recorded at different times for a particular city. The mean of 19.2°C is obtained for 57
temperatures on 57 different days. Assuming that  = 1.8°C, test the claim that the population mean is 21°C.
20. The maximum acceptable level of a certain toxic chemical in vegetables has been set at 0.4 parts per million (ppm). A consumer
health group measured the level of the chemical in a random sample of 72 tomatoes obtained from one producer. The sample had
x  0.57 and s = 0.09.
21. Test the claim that for the population of female college students, the mean weight is given by µ = 132 lb. Sample data are
summarized as n = 20, x  137 lb, and s = 14.2 lb.