1.Z-score is a score that indicates how many ________ an observation is above or below the mean.

standard deviations

means

ranges

z-scores

2.A random sample of 500 immigrants participated in a study about the ethnic background and the level of education of immigrants. Using 1% level of significance and p-value of 0.03, test the claim that ethnic background of immigrants is independent of their level of education.

Yes, they are independent.

No, they are not independent.

We cannot answer the question with the available information.

3.A counselor claims that 20% of all students who take SAT score at least 1200, 25% score between 1000 and 1190, and the remaining 55% score below 1000. A sample of 120 students showed that 20 students had the score of 1200, 35 had a score between 1000 and 1190, while the remaining 65 students scored below 1000. Test the counselor's claim at 0.05 level of significance, using p-value of 50%.

Counselor's claim is valid.

Counselor's claim is not valid.

We cannot answer the question with the available information.

4.A new company came out with a new battery that promised that it would last for more than 8 hours with the standard deviation of 1 hour. A group of researchers studied these batteries. They tested 100 batteries and discovered that they lasted about 8.5 hours. Is company's claim about the new battery supported at the 1% level of significance ()?

Yes

No

We cannot answer the question with the available information.

5.The EPA wants to test randomly selected sample of n water specimens and test the mean daily rate of pollution produced by a mining operation. If the EPA wants a 95% level of confidence and a sampling error of 1 mg/L, how many water specimens are required in sampling? Assume pollution readings in water samples are approximately normal with a standard deviation of 5 mg/L.

97

10

a sample of greater than 30

None of the above

6.Considering question 52 and assuming linear regression equation of Y = 4.6 + 0.2X, how much is the medical cost when pollution reached 6 micrograms?

$4,600.

$23,000.

$1,200

None of the above