# statistics

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.) A hospital in a large city records the weight of every infant born at the hospital. The distribution of weights is normally shaped, with a mea n ยต= 2. 9 kilograms and a standard deviation o- = 0 .45. Determine the following:
a. The percentage of infants who weighed less than 2.1 kilograms
b. The percentile rank of a weight of 4.2 kilograms
c. The percentage of infants who weighed between 1.8 and 4.0 kilograms
d. The percentage of infants who weighed between 3.4 and 4.1 kilograms
e. The weight that divides the distribution such that 1% of the weights are above it
f. Beyond what weights do the most extreme 5% of the scores lie?
g. If 15,000 infants have been born at the hospital, how many weighed less than 3 .5 kilograms?

• statistics -

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z scores. Multiply by 100 to get percentages.

F. Reverse process to get Z score for .05, the use the equation above.

G. multiply proportion found by 15,000.

• statistics -

.oi

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