1 In a paranormal experiment done in the 1970s a subject is

1. In a paranormal experiment done in the 1970\'s, a subject is asked to guess which one of the four letters (ABCD) was written in the other side of the room. The subject made 20 correct guesses out of 50 trials. Researchers claimed that this subject has a success rate significantly different from chance. (Test the claim using a(alpha)=0.05).

2. A recent report claimed that 20% of all college graduates finnd a job in their field of study. A survey of a random sample of 500 graduates found that 100 obtained work in their field. At the significance level of 5%, answer the question :\" Is there statistical evidence to refute the claim?\"

3. The average power consumption of 25 randomly selected families in a community for a given period is 125.6 kilowatt-hours and the standard deviation is 20.3 kilowatt-hours. If we assume that kilowatt usage is normally distributed, is there evidence that the mean usage for the whole community less than 130 kilowatt-hours? Test your hypothesis at the significance level of 0.10.

4. The health of the bear population in Yellowstone National Park is monitored by periodic measurements taken from anesthetized bears. A sample of 54 bears has a mean weight of 182.9 lb., and a standard deviation of 121.8 lb., find a 99% estimate of the mean of the population of all such bear weights.

5. A study was conducted to estimate hospital costs for accident victims who wore seat belts. Twenty randomly selected cases have a distribution that appears to be bell-shaped with a mean of $9,004 and a standard deviation of $5,629. Construct the 99% confidence interval for the mean of all such costs.

Solution