confidence intervals

A researcher selected a sample of 120 milk chocolate bars of 1.6 ounce and found that 90 of them had 230 calories on an average. Find the 90% confidence interval for the true proportion of chocolates with 230 calories. => 67.5% < p < 82.5% or 71% < p < 79% or 69.9% &..

A report states that the average height of females in the U.S who are in between 18 and 25 years of age are approximately 64.8 inches. The mean of the height of 10 females in the age group of 18 to 25 years is found as 62.4 inches with a standard deviation of 2.5 inches. Can one reject the report a..

Select the incorrect statement(s). I. If a confidence interval does not include H 0 , then a hypothesis test will reject H 0 . II. If a confidence interval include H 0 , then a hypothesis test will reject H 0 III.For testing H 0 , t distribution is appropriat..

Which of the statement(s) are not true about degrees of freedom? I. The term "degrees of freedom" is used to describe the number of values in the final calculation of a statistic that are free to vary. II. The degrees of freedom decrease when we have to estimate more parameters. III. The degrees of..

A statistician wishes to see whether the variance of the number of passengers traveling from a particular city to city 1 is different from that to city 2. On observation, it is found that the variance of the number of passengers traveling to city 1 is 250.6 for 30 days and that to city 2 is 105.3 f..

An education department conducted a survey of 400 students on their family background. The results revealed that the mean age of adolescent students who belong to high income families was 15.2 years. The standard deviation of the population is observed as 0.6 years. Find the 99% confidence..

A nutritionist claims that the number of calories in one table spoon of the major brands of pancake syrup is 180. A sample of 18 major brands of syrup is selected and found that the mean number of calories in one tablespoon of syrup is 156 with a standard deviation of 54. At α = 0.1, can the ..

Find the values of c 2 (1 - α/2) and c 2 α/2 for a 99% confidence interval when n = 11. => 26.757, 2.603 or 2.603, 26.757 or 25.188, 2.156 or 2.156, 25.188..

The P & R washing machines manufacturing company conducted tests on different models of washing machines with the same drum size to determine the weights they can withstand. The results (in kgs) are 6, 5.5, 7.8, 6.3, 7.2, and 6.7. Find the 95% confidence interval for the mean we..

The rainfall readings (in millimeters) of 9 cities are listed here. Based on the sample, what is the point estimate of the mean? Find the 90% confidence interval of the population. 2.0, 2.8, 3.1, 4.4, 3.9, 2.6, 5.4, 4.7, 5.2 => 3.79 and 2.87 < μ < 4.71 or 3.9 and 3.15 &..