In hypothesis testing, the significance level represents the probability of

A. committing a Type I error.

B. committing a Type II error.

C. rejecting the null hypothesis when it is in fact false.

D. failing to reject the null hypothesis when it is in fact true.

The monthly salaries of accountants in one region of the country are normally distributed with a mean of Php49000 and a standard deviation of Php4500. What is the probability that a randomly selected accountant in that region earns more than Php52500 a month?

A. 0.1003

B. 0.2184

C. 0.2823

D. 0.7823

A bank's loan officer rates applicants for credit. The ratings are normally distributed with a mean of 200 and a standard deviation of 50. What is the probability that the credit rating of a randomly selected applicant is between 170 and 220?

A. 0.0703

B. 0.1554

C. 0.2257

D. 0.3812

A manufacturer claims that a particular automobile will get at least 50 miles per gallon on the highway. The researchers at a consumer-oriented magazine plans to test this claim with a simple random sample of 30 cars. Assuming that the standard deviation between individual cars is 2.3 miles per gallon, what should the researchers conclude if the sample mean is 49 miles per gallon?

A. There is not sufficient evidence to reject the manufacturer's claim; 49 miles per gallon is too close to the claimed 50 miles per gallon.

B. The manufacturer's claim should not be rejected because the sample mean is less than the claimed mean.

C. The manufacturer's claim should be rejected because the sample mean is less than the claimed mean.

D. The p-value of 0.0086 is sufficient evidence to reject the manufacturer's claim.

A soft-drink dispenser can be adjusted to deliver any fixed number of ounces of soft-drink. If the machine is operating with a standard deviation of 0.3 ounces, what should be the mean setting so that a 12-ounce cup will overflow less than 1% of the time? Assume a normal distribution for the ounces dispensed or delivered.

A. 11.23 oz.

B. 11.30 oz.

C. 11.70 oz.

D. 12.70 oz.

When a true null hypothesis is rejected in a hypothesis test, the researcher or analyst has

A. committed a Type I error.

B. committed a Type II error.

C. made the correct decision.

D. to perform the study again.

The manufacturer of Lakas Papaya cleansing soap claimed that their product was effective in making the facial skin blemish-free of at least 93% of users who tested it for a period of 1 week. In a sample of 350 people who had problems with their facial skin, the soap provided blemish-free skin for 295 people. Which of the following represents the alternative hypothesis for this problem?

A. Ha: p = 0.93

B. Ha: p < 0.93

C. Ha: p > 0.93

D. H_a: p 0.93

The annual incomes of middle management employees is approximately normally distributed with a mean of Php372,000 and a standard deviation of Php8,000. About 68% of the incomes lie between what two income values?

A. Php364,000 and Php380,000

B. Php356,000 and Php388,000

C. Php348,000 and Php396,000

D. Php340,000 and Php404,000