Question

Isabel, an English professor at Pasadena City College was grading essay results. She counted the number of misspelled words in a group of student essays. She noted the distribution of misspelled words per essay followed the normal distribution with a population standard deviation of 2.44 words per essay. For her Tuesday class of 40 students, the mean number of misspelled words was 6.05. Construct a 95% confidence interval for the mean number of misspelled words in the population of student essays. Is it reasonable to conclude that the population mean is 6.79 words (Show work please)

Answer 1

given data are:-

sample mean () = 6.05

sample size (n) = 40

population sd () = 2.44

z critical value for 95% confidence level, both tailed test be:-

a 95% confidence interval for the mean number of misspelled words in the population of student essays is:-

YES, Is it reasonable to conclude that the population mean is 6.79 words. Because , the confidence interval contains the value 6.79.

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