Suppose that BC financial aid alots a textbook stipend by claiming that the average textbook at BC bookstore costs $$ 88.74. You want to test this claim. Based on a sample of 70 textbooks at the store, you find an average of 92.14 and a standard deviation of 29.6. The point estimate is:  (to 3 decimals) The 95 % confidence interval (use z*) is:  to  (to 3 decimals) Based on this we: Reject the null hypothesis Fail to reject the null hypothesis

Suppose a certain species bird has an average weight of x = 3.2 grams. Based on previous studies we can assume that the weights of these birds have a normal distribution with sigma = 0.34 grams. For a small group of 18 birds , find a 98% confidence interval for the average weights of these birds. Write answer in interval notation with two decimal places.

Mrs. Gallas wanted to estimate the average weight of an Oreo cookie to determine if theaverage weight was less than advertised. She selected a random sample of 30 cookies andfound the weight of each cookie (in grams). The mean weight was = 11.1921 grams with astandard deviation of sx = 0.0817 grams. Make a 95% confidence interval to estimate the truemean weight of an Oreo.   1. What is the formula for calculating the standard deviation of the sampling distribution of x? 2.What condition must be met to use this formula? Has it been met?

The mean diastolic blood pressure for a random sample of 50 people was 84 millimeters of mercury. If the standard deviation of individual blood pressure readings is known to be 9 millimeters of mercury, find a 90% confidence interval for the true mean diastolic blood pressure of all people. Then give its lower limit and upper limit. Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.) Lower limit:| ? Upper limit:|

A sample of 20 bags of mulch had a mean weight of 52 pounds with a standard deviation of 3.8 pounds. Find the 95% confidence interval of the true mean. Show all your work for or explain how you obtained your answer in the space provided below.

Suppose that BC financial aid alots a textbook stipend by claiming that the average textbook at BC bookstore costs $$ 88.09. You want to test this claim. Based on a sample of 100 textbooks at the store, you find an average of 85.09 and a standard deviation of 19.8.The point estimate is:  (to 3 decimals)The 99 % confidence interval (use z*) is:  to  (to 3 decimals)

Eden obtains a mark of 67 on her final year exam. Assuming the reliability of the exam is 0.66 and the standard deviation is 10. What is the 95% confidence interval of her mark? What does the interval imply?

Q3. A business man want to decide about the hair-cut prices and so he decided to know the mean time spet on hair-cuts. He has no record of time needed for hair-cut. He wanted a max error of +0.2. He took a sample of size 30 and found that s= 1.5 min. Find the sample size needed to achieve the 95% confidence level.

S9.2. A sample of 15 items provides a sample standard deviation of 6. Develop the 95% confidence interval of the population standard deviation

The lengths of bolts produced in a factory may be taken to be normally distributed. The botlts are checked on two "go-no go" gauges and those shorter tthan 2.9 or longer than 3.1 inches are rejected. A random sample of 50 bolts are checked. If the n1 = 12 and n2 = 12, estimate the mean and the standard deviation for these bolts. State your assumptions. n1  being the number of bolts below 2.9 and n2 is the number of bolts above 3.1.