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LAST KHAN EVER EXAM STUDY GUIDE
SOLUTIONS
A city had an unemployment rate of 7%7%7, percent. The mayor pledged to lower this figure and
supported programs to decrease unemployment - ANSWER✔✔-H0:p=7%
Ha:p<7%
A newspaper report claims that 30%30%30, percent of all tea-drinkers prefer green tea to black tea. Leo
is the office manager at a company with thousands of employees. - ANSWER✔✔-...equal to 30%30%30,
percent.
A quality control engineer is testing the battery life of a new smartphone. The company is advertising
that the battery lasts 242424 hours on a full-charge, but the engineer suspects that the battery life is
actually less than that. They take a random sample of 505050 of these phones to see if their average
battery life is significantly less than 2424 - ANSWER✔✔-H0:μ=24 hours
Ha:μ<24 hours
type ii error-b
A healthcare provider saw that 48%48%48, percent of their members received their flu shot in a recent
year. The healthcare provider tried a new advertising strategy in the following year, and they took a
sample of members to test if the proportion who received their flu shot had changed. - ANSWER✔✔-H0
:p=48%
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Ha:p=48%
Lena is a college basketball player who has made 75%75%75, percent of the free-throws she has
attempted in her career. She decided to practice a new technique for shooting her free-throws. -
ANSWER✔✔-...not equal to 75%75%
A restaurant owner installed a new automated drink machine. The machine is designed to dispense 530
mL530 mL530, start text, space, m, L, end text of liquid on the medium size setting. - ANSWER✔✔-H0
:μ=530 mL
Ha:μ>530 mL
A fair coin should land showing tails with a relative frequency of 50%50%50, percent in a long series of
flip - ANSWER✔✔-H0:p=50%
Ha:p>50%
Reports say that the mean birth weight of babies of European heritage is 3.5 kg3.5 kg3, point, 5, start
text, space, k, g, end text. Marta wants to perform a significance test to see if this holds true in her
nation. - ANSWER✔✔-...equal to 3.5 kg3.5 kg3, point, 5, start text, space, k, g, end text.
A fast-food company advertises that the pre-cooked weight for its burgers is, on average, 0.2 kg0.2 kg0,
point, 2, start text, space, k, g, end text. The company runs a regular quality control test that involves
weighing a sample of burgers to see if the burgers are too light or too heavy. If the sample mean weight
is significantly different than 0.2 kg0.2 kg0, point, 2, start text, space, k, g, end text, then they recycle the
entire batch. - ANSWER✔✔-H0Ha:μ=0.2 kg:μ=0.2 kg
d
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A ketchup company regularly receives large shipments of tomatoes. For each shipment that is received, a
supervisor takes a random sample of 500500500 tomatoes to see what percent of the sample is bruised
and performs a significance test. If the sample shows convincing evidence that more than 10%10%10,
percent of the entire shipment of tomatoes is bruised, then they will request a new shipment of
tomatoes. - ANSWER✔✔-H0:p=0.1
Ha:p>0.1
The National Sleep Foundation recommends that teenagers aged 141414 to 171717 years old get at least
888 hours of sleep per night for proper health and wellness. - ANSWER✔✔-...less than 8 hours.
A local pizza store knows the mean amount of time it takes them to deliver an order is 454545 minutes
after the order is placed. The manager has a new system for processing delivery orders, and they want to
test if it changes the mean delivery time. They take a sample of delivery orders and find their mean
delivery time is 484848 minutes. - ANSWER✔✔-a
A nutritionist suspected that her company's clients had below average cholesterol. They obtained a
random sample of 888 clients of the same age and gender. These clients had a mean cholesterol level of
xˉ=4.28 mmol/Lxˉ=4.28 mmol/Lx, with, \bar, on top, equals, 4, point, 28, start text, space, m, m, o, l,
slash, L, end text (millimoles per liter). - ANSWER✔✔-B .05
An economist read a report that claimed that 60%60%60, percent of residents in her large city owned
their homes. She wondered if that figure was still accurate, so she took a random sample of n=50n=50n,
equals, 50 residents in the city and observed that p^=70%p^=70%p, with, hat, on top, equals, 70,
percent of those sampled owned their homes. - ANSWER✔✔-D
A class in New Zealand found a report suggesting that teenagers' heights in New Zealand are
approximately normally distributed with a mean of 160 cm160 cm160, start text, space, c, m, end text
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