Agrower believes that one in five of his citrus trees are infected with the citrus red mite. how large a sample should be taken if the grower wishes to estimate the proportion of his trees that are infected with citrus red mite to within 0.08 with probability 0.9?

68

Step-by-step explanation:

Formula for sample size when prior estimate of population proportion (p) is available:  

, where z*= critical-value.

E= Margin of error.

Let p be the population proportion of  trees are infected with the citrus red mite.

As per given , we have

E= ± 0.08

The critical z-value corresponding to 90% confidence level = z*=1.645

Substitute all the values in the above formula , we get

Required sample size  :

[Rounded to next integer.]

Thus, the minimum sample size should be taken =68

180

step-by-step explanation:

12-2=10

20-2=18

18x10=180

answer is : muchas/tipicas

have a nice day!

~recklesschicken