Mixed Hypothesis Review #2

Name: ______Mixed Hypothesis Review Activity #2 AP Statistics

1) A consumers group is concerned with the mean cost of dining in a particular restaurant. A random sample of 40 charges (in dollars) per person has a mean charge of $39.7188 with standard deviation of $3.5476. Is there sufficient evidence to conclude that the mean cost per person exceeds $38.00?

2) A national computer retailer believes that the average sales are greater for salespersons with a college degree. A random sample of 34 salespersons with a degree had average weekly sales of $3542 last year, while 37 salespersons without a degree averaged $3301. The standard deviations were $468 for those with a degree and $642 for those without. Is there sufficient evidence to support the retailer’s belief?

3) PTC is a compound that has a strong bitter taste for some people and is tasteless for others. The ability to taste this compound is an inherited trait. Many studies have assessed the proportions of people in different populations who can taste PTC. The following table gives results for samples from several countries. Do they provide evidence that the proportion of PTC tasters varies among the four countries? Ireland Portugal Norway Italy Tasters 558 345 185 402 Non-tasters 225 109 81 134

4) Quart cartons of milk should contain at least 32 ounces. A sample of 22 cartons contained an average of 31.836 ounces with standard deviation of 0.2517 ounce. Does sufficient evidence exists to conclude that the mean amount of milk in all cartons of this brand is less than 32 ounces?

5) Hippocrates magazine states that 37% of all Americans take multiple vitamins regularly. Suppose a researcher surveyed 750 people to test this claim, and he found that 290 regularly take a multiple vitamin. Is this sufficient evidence to conclude that the actual percentage is different from 37%?

6) A die was rolled 60 times with the following results. Is the die a “fair” die? Outcome 1 2 3 4 5 6 Frequency 11 14 8 4 15 8

7) In an experiment on relaxation techniques, subject’s brain signals were measured before and after relaxation exercise with the following results. Is there sufficient evidence to suggest that the relaxation exercise slowed the brain waves? Person 1 2 3 4 5 Before 32 38 65 50 30 After 25 35 56 52 24

8) A private and a public university are located in the same city. For the private university, 1046 alumni were surveyed and 653 said that they attended at least one class reunion. For public university, 791 out of 1327 sampled alumni claimed they had attended a class reunion. Is the difference in the sample proportions statistically significant?