Question

50 percent of a certain product have weight 60 kg or more whereas 10% have weight 55 kg or less. On the assumption of normality, what is the variance of weight?​

Answer 1

Answer:

variance = 3.9 kg

Step-by-step explanation:

Z score = (value - mean)/variance

50 percent of a certain product have weight 60 kg

for 50% z score = 0

value = 60 kg

=> 0 = (60 - mean)/variance

=> mean = 60

10% have weight 55 kg or less.

z score for 10% = -1.282

value = 55 kg

-1.282 = (55 - 60)/variance

=> variance = 5/1.282

=> variance = 3.9

variance = 3.9 kg