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Assuming equal numbers of observations in each of the two samples, find the sample sizes needed to estimate the difference in population means correct to within 2.5 with probability 0.90.  From prior experience, we know that the standard deviation of population 1 is 18 and the standard deviation of population 2 is 16.

The average height of a certain ornamental plant is 14 inches and the standard deviation of the heights is 2 inches.  Find the probability that a randomly selected plant will have a height of more than 17.5 inches.

Null and alternative hypotheses must be stated in terms of population parameters, and not in terms of sample statistics.

Assume that a 90% confidence interval for the mean weight of the population consisting of male students attending OSU is (150 lb,  200 lb).  What is the meaning of this 90% confidence interval?

The mean length of time required to complete the Columbus Marathon was 4.5 hours and the standard deviation of the times was 0.50 hours.  Assume that the racing times were approximately normally distributed.  Only 10% of the runners would be expected to complete the race in less than x hours.  Find the value of x.

Which one of the following statements about the sampling distribution of the sample mean is incorrect?

Frame score in beef cattle is based on height at the hips and is used as a measure of skeletal size.  Frame scores range from 1 to 10 with a higher number indicating a taller animal.  Independent random samples of frame scores were selected from the Angus and Simmental breeds of beef cattle with the following results: Angus Simmental 5 7 6 7 7 8 5 6 7 7 6   Calculate the Total Sum of Squares.

The increasing cost of health care is an important issue today.  Suppose that a random sample of 25 small companies that offer paid health insurance as a benefit was selected.  The sample mean for health insurance cost per worker per month was $300 and the sample standard deviation was $50.  Construct a 90% confidence interval for the population mean (μ).  Assume that any necessary assumptions have been met.

The variables, quantitative or qualitative, that are related to a response variable are called:

A randomized block design is used to compare litter sizes of the Yorkshire and Duroc breeds of sows.  Blocking is used in an attempt to remove the effects of sow age, since it is known that sow age influences litter size.  Each block contains sows of similar ages.  The data collected for this experiment are as follows:                   Yorkshire       Duroc       Block totals Block 1          9 pigs         7 pigs         16 pigs Block 2         10                8                18 Block 3         11                9                 20 Block 4         13              10                 23                                                                             Totals           43              34                 77   The partially completed ANOVA table for this experiment is as follows:   Source          df          SS          MS          F        Total                        23.875 Breed                      10.125      10.125      81.0 Block                       13.375       Error                          0.375                                   Calculate the mean square for blocks and the mean square for error and then calculate the F statistic for blocks.  Do the block means differ (i.e., was blocking effective in removing variation in litter size)?  Use a significance level of α = 0.05.