mean deviation standard deviation learning

Average score of the students in a statistics contest is 65, and the standard deviation is 15. If a random sample of 16 students who participated in the contest are selected, then find the probability that the sample mean of the scores lies between 61 and 67. => 15.52%..

To qualify as a contestant in a swimming event, a swimmer has to be in the top 20% of all entrants. The swimming times are normally distributed, with a mean of 70 min and a standard deviation of 3 min. What is the qualifying time for the event to the nearest minute? =>..

The readings of diastolic blood pressure of a group of volunteers for a medical experiment were normally distributed with a mean of 82 and a standard deviation of 8. If volunteers are to be selected from the middle 50% group, then find the upper and the lower readings,..

30% of the death cases in a hospital are caused by accidents. If 250 cases are selected at random, then find the mean, variance and standard deviation of the number of death cases caused by accidents. => 75, 7.24, 52.5 or 52.5, 75, 7.24 or 7.25, 52.5, 75 or 75, 52.5, 7..

Which of the following statement(s) is/are false? I. The coefficient of nondetermination is found by subtracting the coefficient of determination from 1. II. As the correlation coefficient approaches zero, the coefficient of determination increases more rapidly. III. The standard error of..

Which of the following statement(s) is/are true? I. Standard deviation is never negative. II. Standard deviation is always positive. III. Standard deviation is always zero. IV. Standard deviation may be negative or posi..

Find the standard deviation for the data: 2, 5, 8, 10, 3, 2. => 8.3 or 2.3 or 9.3 or 3.1..

In order to know the causes for deviations from ideality, Van der Waal pointed out the faulty assumption that were made in formulating the kinetic molecular model of gases. The assumption that the volume occupied by the molecular mass is negligible as compared to the total volume of th..

A retail garment shop receives a shipment of trousers, with a standard length of 49.0 in. and a standard deviation of 1.0 inch. A random sample of 32 trousers had a mean length of 48.8 in. Find the standard error. => 5.0 or 3.2 or 1.0 or 0.18..

A random sample of 52 days taken at a chemical laboratory shows that an average of 36 specimens were tested per day. The standard deviation of the population is 6. I. Find the 99% confidence interval of the mean number of specimens tested each day at the laboratory. II..