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For a given sample size, the width of the confidence interval for a parameter increases as the confidence coefficient increases.  In other words, a 95% confidence interval is wider than a 90% confidence interval, and a 99% confidence interval is wider than a 95% confidence interval.

A population of turkeys has a mean weight of 20 lb and a standard deviation of the weights equal to 4 lb.  A turkey breeder selects a large number of samples of 36 turkeys each, calculates the mean weight of the turkeys in each of these samples, and then graphs the sample means. Regardless of the shape of the distribution of the population of turkey weights, would we expect the sample means to be approximately normally distributed?

Find the standard deviation of a binomial probability distribution with a sample size of n = 40 and a probability of success of 0.60.

A random sample of 4,000 U.S. citizens was asked their opinion concerning gun control.  A total of 2,600 of the 4,000 citizens in the sample stated that they are in favor of gun control legislation.  Construct a 98% confidence interval for the true population proportion (p).

Suppose that a random sample of 40 measurements is selected from a population with a mean of 64 and a variance of 64.  What is the mean and standard deviation of the sampling distribution of the sample mean?

Humans possess two sex chromosomes.  A copy of one or the other (equally likely) is contributed to each offspring.  Males have one X chromosome and one Y chromosome.  Females have two X chromosomes.  If a couple has 3 children, what is the probability that they will have at least one boy?

Find the standard deviation of a binomial probability distribution with a sample size of n = 50 and a probability of success of 0.30.

Assume that the mean length of time required to complete the Columbus Marathon was 4.5 hours and that the standard deviation of the times was 0.50 hours.  Assume that the racing times were approximately normally distributed.  What is the probability that a randomly selected runner completed the race in less than 3.6 hours?

A Randomized Block Design is used to compare fleece weights of three breeds of sheep – Merino, Suffolk, and Dorset (we can think of the three breeds as being the three treatments).  The sheep are divided into two weight classes (i.e., two blocks).  Block one contains sheep weighing less than 150 lb and block two contains sheep weighing more than 150 lb.  The fleece weights (in pounds) are as follows:                    Merino          Suffolk          Dorset Block 1          13                  8                  9 Block 2          14                  9                 11                                                                          The partially completed ANOVA table for this experiment is as follows: Source     df          SS            MS            F      Total                29.33333 Breed              26.33333     13.16667    79.00003 Block                     Error                 0.33333        0.16667              The correct values for the Block SS, MS for Blocks, and calculated F value for Blocks, respectively, are:

The owner of a herd of cows wants to determine the influence of the ages of his cows on the amount of calving difficulty that occurs in his herd.  He constructs the following table:                             Age of Cow (in years)                                           0-2     3-5     6-10     over 10   Total No difficulty     40      35       20          5            100 Difficult birth   35      45       15          5            100 Total                  75      80       35        10           200   Find the probability that a randomly selected cow had difficulty in giving birth to her calf and was over 10 yr old.