b) An achievement test was administered to a class of 20,000 students. The mean score was 80 and the standard deviation was 11. If Lingard scored 72 in the test, how many students did better than him

15328

Step-by-step explanation:

The following can be deduced from the information given:

N = 20000

μ = 80

σ = 11

P(X>72) = 1 - P (X<72)

= 1 - P(Z < 72-80/11)

= 1 - P(Z < -8/11)

= 1 - P(Z < 0.7272)

= 1 - 0.2336 = 0.7664

Therefore, the number of students that were better than Lingard n(X > 72) will be:

= 20000 × 0.7664

= 15328