5.Given thatZis a standard normal variable, the valuezfor whichP(Zz) = 0.2580 is:

Select one:

a.0.70.

b.0.758.

c.-0.65.

d.0.242.

6.If the continuous random variableXis uniformly distributed over the interval [15, 25], then the mean ofXis:

Select one:

a.40.

b.25.

c.20.

d.15.

7.The objective of estimation is to determine the approximate value of:

Select one:

a.a sample statistic.

b.a population parameter.

c.the sample mean.

d.the sample variance.

9.For a sample of size 30 taken from a normally distributed population with standard deviation equal to 5, a 95% confidence interval for the population mean would require the use of:

Select one:

a.z= 1.96.

b.z= 1.645.

c.t= 2.045.

d.t= 1.699.

10.Thezvalue for a 95% confidence interval estimate is:

Select one:

a.2.12.

b.1.82.

c.2.00.

d.1.96.

12.A point estimate is defined as:

Select one:

a.the average of the sample values.

b.the average of the population values.

c.a single value of an estimator.

d.an interval within which the population parameter is believed to lie .

I dont need explaination