Question

Suppose that 75% of the properties in Highland are houses. If I pick a sample of 200 random properties, what is the probability that less than 155 houses in the sample?

Answer 1

Let X denote the number of houses in the 200 randomly chosen properties.

Clearly X=0,1,2,...,200

Selecting a house is treated as success.

Here,

Since sample size n is very large we can use central limit theorem and hence Normal approximation.

For normal distribution,

We have,

Required probability is,

The value is obtained from standard normal table.

answered by: anonymous