The average value of a group of data is 153.2, and the standard deviation is 9.36. The probability that the value is greater than or equal to 160 When any data in the group is selected is calculated
When the sample size is large, X approximately follows the normal distribution n (153.2,9.36 ^ 2), then u = (x-153.2) / 9.36 ~ n (0,1),
P(X≥160)
=P{(X-153.2)/9.36 ≥{(160-153.2)/9.36 }
=P(U≥0.7265)
=1-P(U≤0.7265)
=1-0.7661=0.2339