The ages of commercial aircraft are normally distributed with a mean of 12.0 years and a standard deviation of 8.3866 years. what percentage of individual aircraft have ages between 9 years and 15 years? assume that a random sample of 81 aircraft is selected and the mean age of the sample is computed. what percentage of sample means have ages between 9 years and 15 years?

Anew shopping mall is gaining in popularity. every day since it opened, the number of shoppers is 5% more than the number of shoppers the day before. the total number of shoppers over the first 10 days is 1258 how many shoppers were on the first day?

#7. m is the midpoint of pq, the diameter of the circle o is 13in. and rm = 4in. find pm find pq

Atest of sobriety involves measuring the subject's motor skills. a sample of 31 randomly selected sober subjects take the test and produce a mean score of 64.4 with a standard deviation of 2. a claim is made that the true mean score for all sober subjects is equal to 65. for each part below, enter only a numeric value in the answer box. for example, do not type "z =" or "t =" before your answers. round each of your answers to 3 places after the decimal point. (a) calculate the value of the test statistic used in this test. test statistic's value = (b) use your calculator to find the p-value of this test. p-value = (c) use your calculator to find the critical value(s) used to test this claim at the 0.2 significance level. if there are two critical values, then list them both with a comma between them. critical value(s) =