Objective type problems based on the Confidence interval and regression.
1) Mean=63.6 Standard deviation=2.5 If 36 data points are randomly selected, find the probability that the mean is less than 64.
a. .3815
b. .8315
c. .1685
d. .5183
2) Express the confidence interval .600, .800 in the form p hat plus and minus E.
a. .700 plus and minus .005
b. .700 plus and minus .500
c. .700 plus and minus .010
d. .700 plus and minus .100
3) Find the 95% confidence interval of the population mean, given n=90, x bar=66.2 and standard deviation=3.4.
a. 34.5, 35.5
b. 33.1, 34.5
c. 60.0, 70.0
d. 65.5, 66.9
4) 1,025 randomly selected adults were surveyed and 29% of them said they used the internet for shopping. Find a 99% confidence interval for the proportion of adults who use the internet for shopping.
a. .253, .326
b. .200, .300
c. .203, .303
d. .214, .316
5) Claim u=75. Sample data n=15, x bar=66, s=12. Sigma = 14. Which distribution should be used to test the claim that the population mean=75.
a. Student t
b. Normal
c. Binomial
d. None of these
6) The mean lifespan of desktop PCs is less than 7 years. Assume data come from a normal population. n=21, x bar=6.8, s=2.4, alpha=.05 Compute the critical t value of the data.
a. +1.725
b. -1.645
c. -1.725
d. +1.645
7) Find the equation of the regression line from the following data: x: 1, 1, 2, 5, 3 y: 0, 2, 2, 3, 5
a. y hat = .333 + .667x
b. y hat = .857 + .643x
c. y hat = .643 + .857x
d. y hat = 10 + x
8) Find the equation of the regression line. x: 0, 2, 1, 4, 8 y: 6, 5, 4, 0, 6
a. y hat = 2.275 - 0.025x
b. y hat = 4.725 + 0.065x
c. y hat = 4.275 - 0.025x
d. y hat = 3.275 - 0.035x