Answer:
The probability of 213 or fewer cases of such cancer in a group of 479,908 people is 0.2776.
Step-by-step explanation:
We are given that assuming that cell phones have no effect, there is a 0.000462 probability of a person developing cancer of the brain or nervous system. We, therefore, expect about 222 cases of such cancer in a group of 479,908 people.
Let = <u><em>sample probability of a person developing cancer of the brain or nervous system.</em></u>
The z-score probability distribution for the sample proportion is given by;
Z = ~ N(0,1)
where, p = population probability of a person developing cancer of the brain or nervous system = 0.000462
n = sample of cell phone users = 479,908
Now, the probability of 213 or fewer cases of such cancer in a group of 479,908 people is given by = P(
)
P(
0.000444) = P(
) = P(Z
-0.59)
= 1 - P(Z < 0.59) = 1 - 0.7224 = <u>0.2776</u>
The above probability is calculated by looking at the value of x = 0.59 in the z table which has an area of 0.7224.
These results suggest about media reports that cell phones cause cancer of the brain or nervous system that there is around 28% chance that 213 or fewer cases of such cancer in a group of 479,908 people can take place.