Answer:
a) 
The degrees of freedom are given by:
The critical value for this case is 
since the calculated value is higher than the critical we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 18.4
b) 
Step-by-step explanation:
Information given
represent the sample mean
represent the sample standard deviation
sample size
represent the value to verify
represent the significance level
t would represent the statistic
represent the p value
Part a
We want to test if the true mean is higher than 17.5, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
The statistic is given by:
(1)
And replacing we got:
The degrees of freedom are given by:
The critical value for this case is since the calculated value is higher than the critical we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 18.4
Part b
The p value would be given by:
Answer:
Step-by-step explanation:
Move all terms that don't contain
x
to the right side and solve.
x
=
6
+
3
y
2
10% of 90 is 9. You can try cross multiplying.
9 times 5 equals 45 so yes
