Question

​(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 21 second grade students was 92.7 wpm. What might you conclude based on this​ result? Select the correct choice below and fill in the answer boxes within your choice.​(Type integers or decimals rounded to four decimal places as​ needed.)

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 (f). (Type integers or decimals rounded to four decimal places as needed.) A. A mean reading rate of 92.7 wpm is unusual since the probability of obtaining a result of 92.7 wpm or more is . This means that we would expect a mean reading rate of 92.7 or higher from a population whose mean reading rate is 90 in of every 100 random samples of size n= 21 students. The new program is abundantly more effective than the old program. OB. A mean reading rate of 92.7 wpm is not unusual since the probability of obtaining a result of 92.7 wpm or more is . This means that we would expect a mean reading rate of 92.7 or higher from a population whose mean reading rate is 90 in of every 100 random samples of size n=21 students. The new program is not abundantly more effective than the old program.

Answer 1

X21 be the reading speed of 21 student =) Xi ~ N(80, 10²) N (90, 10 2 =) ! ) 21 so IP (X> 92.7) P (2>92.7) when Z~N 190,102) 21 0.108 og obsewe (asing Standard Calculator 7 out of 100 cases we will approximately in $10.8 (or approximately 11) samples the mean mean reading than 92.7 = This is unusual rate is higher (A） The mean mou is would expect 92-2 wpm os This means that we 0.108 mean in U of every reading rate is so 100 samples of size n=21.