29) The mean IQ score of students in a particular calculus class is 110, with a

Question

29) The mean IQ score of students in a particular calculus class is 110, with a standard deviation of5. 29) Use the Empirical Rule to find the percentage of students with an IQ above 120. (Assume the data set has a bell-shaped distribution.) A) 13.5% B) 2.5% C) 11.15% D) 15.85% 30) Assume that male and female births are equally likely and that the birth of any child does not affect 30) the probability of the gender of any other children. Find the probability of at most three boys in ter births A) 0.003 B) 0.333 C) 0.172 D) 0.300 31) A recent survey found that 70% of all adults over 50 wear glasses for driving. In a random sample 31) of 10 adults over 50, what is the probability that at least six wear glasses? A) 0.700 B) 0.200 C) 0.850 D) 0.006 32) Assume that male and female births are equally likely and that the birth of any child does not affect 32) the probability of the gender of any other children. Find the probability of exactly eight boys in ten births. A) 0.08 B) 0.176 C) 0.044 D) 0.8 33) Many firms use on-the-job training to teach their employees computer programming. Suppose you work in the personnel department of a firm that just finished training a group of its employees to program, and you have been requested to review the performance of one of the trainees on the final test that was given to all trainees. The mean and standard deviation of the test scores are 72 and 5, respectively, and the distribution of scores is bell-shaped and symmetric. Suppose the trainee in question received a score of 68. Compute the trainee's z-score A) z = 0.88 B) z -0.88 C) z--0.80 D) z = 0.8

Explanation / Answer

As per the Chegg policy, we are advised to do only one question at a time so i am attempting 29th.

29. As per the empirical rule:

68% of observations lie between 1 standard deviation from the mean.

95% of observations lie between 2 standard deviation from the mean.

99.7% of observations lie between 3 standard deviation from the mean.

Hence,

P(X > 120)

= P(z > (120 - 110)/5)

= P(z > 2)

= 2.5% [Since 95% is covered within z = -2 and z = 2, 2.5% will remain on either side of the curve]

Option B is correct.

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