Question
The average life expectancy of Canadian women is 75 years, and is normally distributed. The standard deviation is known to be 7 years. If a random sample od 49 women is taken, what is the probability that the average age of the sample of women is:
Between 73.5 and 76 years?
Between 72 and 74 years?
Less than 72.7 years?
Between 73.5 and 76 years?
Between 72 and 74 years?
Less than 72.7 years?
Answers
PsyDAG
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z scores.
Z = (score-mean)/SEm
SEm = SD/√n
Z = (score-mean)/SEm
SEm = SD/√n
pam
73.5-76=2.5/7 = 0.357