Question

The reading speed of second grade students in a large city is approximately​ normal, with a mean of 90

words per minute​ (wpm) and a standard deviation of 10 wpm. Complete parts​ (a) through​ (e).

(a) What is the probability a randomly selected student in the city will read more than 94 words per minute? (Round to four decimal places as needed.)

(b) What is the probability that a random sample of 12 second grade students from the city results in a mean reading rate of more than 94 words per minute? (Round to four decimal places as needed.)

(c) What is the probability that a random sample of 24 second grade students from the city results in a mean reading rate of more than 94 words per​ minute? (Round to four decimal places as needed.)

(d) What effect does increasing the sample size have on the​ probability? Provide an explanation for this result.

(e) A teacher instituted a new reading program at school. After 10 weeks in the​ program, it was found that the mean reading speed of a random sample of 19 second grade students was 92.3 wpm. What might you conclude based on this​ result?

Answer 1