The mean value of land and buildings per acre from a sample of farms is ​$1300​, with a standard deviation of ​$100. The data set has a​ bell-shaped distribution. Assume the number of farms in the sample is 76. ​(a) Use the empirical rule to estimate the number of farms whose land and building values per acre are between ​$1100 and ​$1500.

Respuesta :

So we are looking to compute the following formula:
[tex]P(1100\ \textless \ X\ \textless \ 1500)= P(\frac{1100-1300}{100}\ \textless \ N\ \textless \ \frac{1500-1300}{100})\\=P(-2\ \textless \ N\ \textless \ 2)\text{ (Wherein N is the normal law (0,1))}.\\=0.95[/tex]

Answer: The probability is 0.95. 
Now, in order to get the number of farms, multiply the whole number by the probability like this: 0.95*76 = 72. 
Answer: 72 farms