3) In a speech to the Chamber of Commerce, a city councilman claims that in his city less than 15% of
the adult male population are unemployed. An opponent in the upcoming election wants to test the
councilman’s claim.
Ho: p = 0.15
Ha: p < 0.15
4) The councilman is starting to get worried about the upcoming election. He has enjoyed 63% support
for several years, but the political climate has been changing. He wants to know if his support has
changed.
Ho: p = 0.63
Ha: p  0.63
5) A production process is considered to be under control if the machine parts it makes have a mean
length of 35.50 mm with a standard deviation of 0.45 mm. Whether or not the process is under control
is decided each morning by a quality control engineer who bases his decision on a random sample of
size 36. Should he ask for an adjustment of the machine on a day when he obtains a mean of 35.62 mm?
Ho:  = 35.5
Ha:   35.5
6) Jim, the owner of Jim’s Grocery, knows that Plain Chips have always outsold Spicy chips. However,
sales of Spicy chips have been increasing. Jim wants to determine if the average weekly sales of Spicy
chips have indeed surpassed that of Plain chips.
Ho:  (spicy)=  (plain)
Ha:  (spicy) >  (plain)
7) Jim now wants to know if Plain and Spicy chips have the same percentage of defective product (i.e.
underfilled bags, torn bags, wrong flavor in the bags, etc.).
Ho: p (spicy)= p (plain)
Ha: p (spicy)  p (plain)
8) The Great Vehicle Co. just introduced New SUV, claiming it can pull more weight than Old SUV. After
testing 150 vehicles of each model, Old SUV had a mean pull weight of 5032 pounds with a standard
deviation of 72 pounds. New SUV had a mean pull weight of 5462 pounds with a standard deviation of
154 pounds. Is the claim valid at a .05 level of significance?
Ho:  (New)=  (Old)
Ha:  (New) >  (Old)
9) The Great Vehicle Co. has a competitor, Amazing Autos, that claims people who purchase its
competing vehicle, the Sport Off Road Vehicle (SORV), have higher customer satisfaction than New SUV.
Out of 736 people who purchased the SORV last month, 534 said they were satisfied. Out of 521 people
who purchased New SUV last month, 375 said they were satisfied. Is there a higher percentage of
people who are satisfied with the SORV than with New SUV?
Ho: p (Sorv)= p (New Suv)
Ha: p (Sorv) > p (New Suv)
10) The Great Vehicle Company wants to counter Amazing Autos’s claim by making its own claim that
New SUV has a lower percentage of defective vehicles. The research team tested 536 vehicles of each
model and found that SORV had 53 defective units, while New SUV had only 51 defective units.
Ho: p (New Suv)= p (Sorv)
Ha: p (New Suv) < p (Sorv)