If a sample of n elements is selected from a population of N elements using a sampling plan in which each of the possible samples has the same chance of being selected, then the sampling is said to be random and the resulting sample is a simple random sample.
Indicate whether the statement is true or false
Q. 2As the degrees of freedom for the t-distribution increase, the distribution approaches the:
a. chi-square distribution
b. t distribution
c. z distribution
d. normal distribution
e. F distribution
Q. 3Given that X is a binomial random variable, the binomial probability P(X <= x) is approximated by the area under a normal curve to the left of:
a. x
b. -x
c. x + 0.5
d. x - 0.1
e. -x - 0.1
Q. 4When finding a confidence interval for a population mean based on a sample of size 8, which assumption is made?
a. The population standard deviation, is known.
b. The sampling distribution of z is normal.
c. The sampled population is approximately normal.
d. There is no special assumption made.
e. None of these.
Q. 5Given that X is a binomial random variable, the binomial probability P(X = x) is approximated by the area under a normal curve between:
a. x - 0.5 and 0.0
b. 0.0 and x + 0.5
c. 1 - x and 1 + x
d. x - 0.5 and x + 0.5
e. 0.0 and x + 1
Q. 6For a t-distribution with 12 degrees of freedom, the area between -2.6810 and 2.1788 is 0.980.
Indicate whether the statement is true or false
Q. 7Suppose that the probability p of success on any trail of a binomial distribution equals 0.90 . Then for which of the following number of trials, n, would the normal distribution provide a good approximation to the binomial distribution?
a. 25
b. 35
c. 45
d. 55
e. 65
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