Question

The brain volumes (cm cubedcm3 )of 20 brains have a mean of

1155.1cm cubedcm3and a standard deviation of

129.1cm cubedcm3.Use the given standard deviation and the range rule of thumb to identify the limits separating values that are significantly low or significantly high. For such data, would a brain volume of1453.3cm cubedcm3 be significantly high?

Significantly low values are__cm cubedcm3or lower.

(Type an integer or a decimal. Do not round.)

Significantly high values are__cm cubedcm3or higher.

(Type an integer or a decimal. Do not round.

Is1453.3cm^3 significantly high?

Answer 1

It is given that mean = 1155.1 cm3

standard deviation = 129.1 cm3

We know that by range rule of thumb, any values which are equal to   or lower and equal to or higher are considered as significant values.

= 1155.1 -(2*129.1)= 1155.1-258.2 = 896.9 cm3

= 1155.1 + (2*129.1)= 1155.1+258.2 = 1413.3 cm3

So, values between 896.9cm3 and 1413.3cm3 will not be considered as significant and

all values equal to or greater than 1413.3cm3 will be considered as significant high values

equal to or less than 896.9cm3 will be considered as significant low values

1453.3cm3 is greater than 1413.3 cm3, so it is a significant value.