**Use your calculator to find the areas (percent of data) that satisfy the stated conditions for each normal distribution. Round each answer to four decimals. **

**1) Greater than 67, if the mean is 60 and the standard deviation is 15**

**2) Less than 70, if the mean is 63 and the standard deviation is 14**

**Should I go 2nd than VARS, than 2:normal cdf( ?????**

**I tryied already but it does not work!! please help!**

### 1 Answer | Add Yours

(1) Given `mu=60,sigma=15` find `P(x>67)`

First convert 67 to a standard z-score: `z=(67-60)/15=7/15=.4bar(6)`

Then `P(x>67)=P(z>7/15)` . In a TI-83/84 calculator you follow the following steps:

2nd VARS (dist)->2 (normalcdf)

On the homescreen you will see normalcdf(

Input `7/15`

Then ,

Then ``2nd , (EE) 99

Close parantheses and hit enter. The result should be .3203692025

**Alternatively, you can skip converting to a standard z-score. Input normalcdf(67,E99,60,15) and you will get .3203692025 as before. The format is normalcdf`(a,b,mu,sigma)` where a is the lower limit and b the upper limit.

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**Thus `P(x>67)~~.3204` **

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** This is the area under the standard normal curve from .466666667 to infinity **

(2) Input normalcdf(-E99,70,63,14) and the result should be .6914624678

** Make sure to use the opposite key "-", not the subtract key.**

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`"Then" P(xlt70)~~.6915`

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