an english teacher has been teaching a sixth grade composition class for many years he has a feeling that over the past several years the writing ability of students has changed. a national test of proficiency in composition was administered 5 years ago. the resulting distribution of scores was normally shaped had a population mean of 85 and a population standard deviation of 10.9 in order to test his feeling he gives his present class of 43 students the same proficiency test. the resulting mean is 80 and standard deviation is 8.7 the obtained value of the appropriate statistic for testing h0 is

What is the ratio for the surface areas of the cones shown below, given that they are similar and that the ratio of their radii and altitudes is 2: 1? submit

According to a research study, parents with young children slept 6.4 hours each night last year, on average. a random sample of 18 parents with young children was surveyed and the mean amount of time per night each parent slept was 6.8. this data has a sample standard deviation of 0.9. (assume that the scores are normally distributed.) researchers conduct a one-mean hypothesis at the 5% significance level, to test if the mean amount of time parents with young children sleep per night is greater than the mean amount of time last year. the null and alternative hypotheses are h0: μ=6.4 and ha: μ> 6.4, which is a right-tailed test. the test statistic is determined to be t0=1.89 using the partial t-table below, determine the critical value(s). if there is only one critical value, leave the second answer box blank.

15. jiovanni is looking in to two different companies that offer study guides for math exams. test prep 101 charges a $5 flat fee and an additional $0.25 per problem. math charges a $2 flat fee and an additional $0.50 per problem. how many prablems would make the costs of the two companies be equal? varibles: equations/eniqualities{ {