Answer: 0.6827
Step-by-step explanation:
Given : Mean IQ score :
Standard deviation :
We assume that adults have IQ scores that are normally distributed .
Let x be the random variable that represents the IQ score of adults .
z-score :
For x= 90
For x= 120
By using the standard normal distribution table , we have
The p-value :
Hence, the probability that a randomly selected adult has an IQ between 90 and 120 =0.6827
Answer:
a) P=0.03
b) α=0.05
c) 0.72
d) 100
e) 0.72
Step-by-step explanation:
a) The P-value is the probability of the sample result. In this case the P-value is 0.03.
b) The level of significance is the threshold of probabilty for the null hypothesis to be reejcted or not. It is contrasted with the P-value to know if the effect is significant. In this case, the level of significance is 0.05.
NOTE: if it is a two-side test, the level of significance is 0.1 (two times 0.05).
c) The sample proportion is the one that results from the sample data. In this case, the sample proportion is 0.72.
d) The sample size is the amount of consumers reported. In this case is 100 customers.
e) The null value is 0.72 (equal to the sample proportion), because it is tested if there is no difference between the population proportion and the sample proportion.