You need to find the slope
251-248. 3
------------- = --------
2005-1965. 40
-3(k+7)-5k+4=23
-3k-21-5k+4=23
Get rid of the numbers that aren't being multiplied by k:
-3k-5k=23+21-4
Add like things:
-8k=40
Divide by -8 on both sides to get k by itself and to make the equation even:
k=-5
Answer:

And for this case we can use the complement rule and the normal standard distribution of excel and we got:

Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the heights of a population, and for this case we know the distribution for X is given by:
Where
and
And we select a sample size of n =70
From the central limit theorem (n>30)we know that the distribution for the sample mean
is given by:
And we want to find this probability:

And we can use the z score formula given by:

And using this formula we got:

And for this case we can use the complement rule and the normal standard distribution of excel and we got:
