Statistics - Confidence Interval

Please provide step by step instructions using actual numbers instead of formulas for solving the following 3 problems, thanks

3. Determine whether the average number of calories in a homemade cookie is more than a store-bought one. Estimate the difference in the mean calories between the two types using a 90% confidence interval.
homemade n=40 x-bar=180 s=2
storebought n=45 x-bar=179 s=4


4. A childcare agency was interestin in examining the amount that families pay per child per month for childcare outside the home. A randome sample of 64 families was selected and the mean and the standard deviation were computed to be $675 and $80 respectively.
a. Find a 95% confidence interval for the true average amount spent per child per month for childcare outside the home.
b. Interpret the interval found in part a.
c. A social worker claims that the average amount spent per child per month outside the home is $700. Based on the interval in part a can this claim be rejected?
d. Find a 95% upper confidence bound for the true average amount spent per child per month on childcare outside the home.