The average number of mosquitoes in a stagnant pond is 60 pe

The average number of mosquitoes in a stagnant pond is 60 per square meter with a standard deviation of 16. If 64 square meters are chosen at random for a mosquito count, find the probability that the first square meter has more than 62.9 mosquitoes.

Select one:

a. 7%

b. 18%

c. 32%

d. 43%

e. Cannot be determined

Solution

We first get the z score for the critical value. As z = (x - u) / s, then as          
          
x = critical value =    62.9      
u = mean =    60      
          
s = standard deviation =    16      
          
Thus,          
          
z = (x - u) / s =    0.18125      
          
Thus, using a table/technology, the right tailed area of this is          
          
P(z >   0.18125   ) =    0.428085675 = 43% [ANSWER, OPTION D]