contestada

The lengths of one-year-old baby girls can be described using a normal distribution with a mean of 29 inches and a standard deviation of 1.2 inches. using the empirical '68-95-99.7' rule, what percent of one-year-old girls are between 26.6 and 31.4 inches?

Respuesta :

The '68-95-99.7' rule says

-About 68% of values fall within one standard deviation of the mean.

-About 95% of the values fall within two standard deviations from the mean.

-Almost all of the values — about 99.7% — fall within three standard deviations from the mean.

Here

[tex] 26.6=29-2*1.2
31.4=29+2*1.2 [/tex]

Hence the values fall within two standard deviations from the mean. The corresponding percentage is 95%.