Try z-scores:
z = (x - mean)/sd
Substitute the data into the above formula and solve for x.
mean = 11.5
sd = 2.7
z = score from the table
Use the table to find z-score at the 80th percentile.
I'll let you take it from here.
The weights of male babies less than 2 months old in the United States is normally distributed with a mean of 11.5 pounds and a standard deviation of 2.7 pounds.
Find the 80th percentile score for these weights.
1 answer