Question

Having some trouble and e and f

The reading speed of second grade students is approximately normal, with a mean of 90 words per minute (wpm) and a standard deviation of 10 wpm. Complete parts (a) through (f). W YYTIUL CICUL uuww mercury the Jumpiu JILU TUYU UIT ITU MODUULI TUYTUU UIT WATUITULIOI TOT CITU TUVUT O A. Increasing the sample size increases the probability because of decreases as n increases. OB. Increasing the sample size decreases the probability because of increases as n increases. OC. Increasing the sample size increases the probability because of increases as n increases OD. Increasing the sample size decreases the probability because of decreases as n increases (e) Ateacher 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 20 second grade students was 92.2 wpm. What might you conclude based on this result? Select the correct choice and fill in the answer box in your choice below. (Round to four decimal places as needed.) O A. Amean reading rate of 92.2 wpm is unusual since the probability of obtaining a result of 92.2 wpm or more is . The new program is abundantly more effective than the old program. OB. Amean reading rate of 92.2 wpm is not unusual since the probability of obtaining a result of 92.2 wpm or more is the new program is not abundantly more effective than the old program. (There is a 5% chance that the mean reading speed of a random sample of 20 second grade students will exceed what value? wpm. There is a 5% chance of the mean value exceeding (Round to one decimal place as needed.) Click to select your answer(s).

Answer 1

e)

for normal distribution z score =(X-μ)/σ
here mean=       μ=	90
std deviation   =σ=	10
sample size       =n=	20
std error=σx̅=σ/√n=	2.2361

probability =

P(X>92.2)

=

P(Z>0.98)=

1-P(Z<0.98)=

1-0.8365=

0.1635

option B: .......92.2 wpm or more is 0.1635 . ......not abundantly more effective,,,,,,,,

f)

for 95th percentile critical value of z=		1.645
therefore corresponding value=mean+z*std deviation=			93.7