confidence intervals

In a survey of 500 canned fish, 150 fish has a potassium content of 3800 ppm. Find the 95% confidence interval for the true proportion of canned fish whose potassium content is 3,800 ppm. => 22.7% < p < 37.3% or 26% < p < 34% or 26.3% < p < 33.7% or 66% < p ..

An automobile parts supplier wants to know how long car owners plan to keep their cars with them. A random sample of 20 car owners results in a standard deviation of 3.7 years. Find a 95% confidence interval for the variance and standard deviation. Assume that the variable is no..

Select the incorrect statement(s). I. The z ∝ /2 for the 90% confidence interval is 1.55. II. The z ∝ /2 for the 95% confidence interval is 1.96. III. The z ∝ /2 for the 99% confidence interval is 2.58. => II only or all are..

A company makes wooden wardrobes having a standard height of 55 in., with a standard deviation of 2.5 in. In a random sample of 23 wardrobes, 6 wardrobes measured 58.5 in., 8 wardrobes measured 53.8 in. and 9 wardrobes measured 56 in.. Find the 95% confidence interval. => The ..

Select the incorrect statement. I. For a 95% confidence interval for the mean, when the sample size is 26, the value of t ∝ /2 is 2.036. II. For a 98% confidence interval for the mean, when the sample size is 19, the value of t ∝ /2 is 2.552. III. F..

The mean number of candies in a packet is 175, with a standard deviation of 5 candies. A random sample of 70 packets from a certain shipment has a mean of 174.2 candies. Which of the following statements is true? 1.The null hypothesis is accepted. 2.Standard error = 1.78 3.The shipment is significa..

The report of a municipal corporation states that the average monthly electricity bill of a household in the city is $75. To test this report, a researcher selected a sample of 120 residential electricity bills and found the mean as $76.50 with a standard deviation of $15. At α = 0.01. Can th..

Find the values of c 2 (1 - α/2) and c 2 α/2 for a 80% confidence interval when n = 4. => 0.584, 6.251 or 7.779, 1.064 or 6.251, 0.584 or 1.064, 7.779..

A manufacturer developed a new nickel - metal hydride battery to be used in mobile phones as a possible replacement for the old nickel - cadmium batteries. The performance measure of interest is the talking time (in minutes) available prior to recharging the battery. The result of test conducted on..

The prices of 1 gallon of premium gasoline in U.S dollars in a sample of seven foreign countries is shown. What is the point estimate for the mean? Find the 98% confidence interval of the mean for the prices of 1 gallon of premium gasoline in U.S. 3.80, 3.20, 3.80, 3.57, 3.62, 3..