Complete Question
Statistics professors believe the average number of headaches per semester for all students is more than 18. From a random sample of 15 students, the professors find the mean number of headaches is 19 and the standard deviation is 1.7. Assume the population distribution of number of headaches is normal.the correct conclusion at
is?
Answer:
There is no sufficient evidence to support the professor believe
Step-by-step explanation:
From the question we are told that
The population mean is 
The sample size is 
The sample mean is 
The standard deviation is 
The level of significance is 
The null hypothesis is 
The alternative hypothesis is 
The critical value of the level of significance from the normal distribution table is

The test hypothesis is mathematically represented as

substituting values


Looking at the value of t and
we can see that
so we fail to reject the null hypothesis.
This mean that there is no sufficient evidence to support the professor believe