Question

Of 400 students, 150 are male students and 250 are female students, 60 of the male students and 90 of the female students fail the statistics course. A student is selected at random from these 400 students. What is the probability that the selected student would be a male or fail the statistics course?

Select one:

a. 0.525

b. 0.15

c. 0.75

d. 0.6

A prospective developer of a shopping mall in an area believes that the average annual income per capita in the area is $280,000. Historical data suggest that for the type of area involved, household incomes per capita are skewed. The population standard deviation can be accepted as being equal to $22,000, based on an earlier study. The prospective developer wants to estimate the true mean annual income per capita in the area. For a random sample of 25 individuals, the mean annual income is found to be $265,000. Using the 95% confidence level, what is the interval estimate of the true mean income per capita in the area?

Select one:

a. $255,918.84 to $274,081.16

b. No solution

c. $256,376 to $273,624

d. $271,376 to $288,624

Answer 1

Q 1

	fail	pass	Total
male	60	90	150
female	90	160	250
Total	150	250	400

P(male or fail) = P (male) + P (fail) - P(male and fail) = 150/ 400 + 150/400 - 60/400 = 240 / 400 = 0.60

ANS: Probability that the selected student would be a male or fail the statistics course = 0.60

Q 2

n = 25

= 22000

sample mean = 265000

z value for 95% CI = 1.960

CI = mean + /- E

CI = 265000 +/ - 8624

CI = 256376 , 273624

ANS: Option c. $256,376 to $273,624