Baby weights the weight of male babies less than 2 months...

Baby weights: The weight of male babies less than 2 months old in the United States is normally distributed with mean 12.3 pounds and standard deviation 4.7 pounds . Use the TI-83 Plus/TI-84 Plus calculator to answer the following. Round the answers to four decimal places. (b) What proportion of babies weigh less than 15 pounds ? The proportion of babies weighing less than 15 pounds is

Transcript

00:01 So we have the weights of babies that are less than two months old are normally distributed.

00:07 So we're dealing with that bell shape curve.

00:09 And the mean is 12 pounds with a standard deviation of 3 .7 pounds.

00:20 And we're going to use our calculator function to answer the following questions.

00:25 And we're rounding to four decimal places.

00:29 So when you're using the.

00:32 The graphing calculator to calculate these probabilities, we're going to use the normal cdf or cumulative density function to do so.

00:45 And when you use that function on the ti -84, you have to describe the lower boundary, the upper boundary, the mean, and the standard deviation.

01:04 So in part a, we are trying to determine what proportion of babies weigh more than 13 pounds.

01:13 So 13 would be greater than the mean, so it's going to be over here, and we're talking about this portion right here.

01:20 So our lower boundary is going to be 13.

01:24 So we're going to say normal cdf.

01:30 Now our upper boundary, keep in mind that tail on the right continues infinitely on.

01:36 So we're going to pick a super large number.

01:38 Let's pick 10 to the 99.

01:40 9th power.

01:41 And then we'll follow it up using the mean.

01:43 The mean was 12 and the standard deviation was 3 .7.

01:48 So i'm going to bring in my calculator.

01:53 So my calculator is right here.