Which of the following situations calls for a hypothesis test about a population mean?

a. According to the Center for Disease Control (CDC), roughly 21.5% of all U. S. highschool seniors in 2002 have used marijuana. A sociologist suspects that the rate among African-American high school seniors is lower.

b. A recent study estimated that 20% of all college students in the United States smoke. The head of Health Services at Goodheart University suspects that the proportion of smokers may be lower there.

c. A certain prescription allergy medicine is suppose to contain an average of 245 parts per million (ppm) of active ingredient. The manufacturer wants to check whether the mean concentration in a large shipment of pills is 245 ppm or not.

d. A report on the College Board website stated that in 2003 males scored generally higher than females on the SAT exam. An educational researcher wants to check whether this is true in her school district.

Step-by-step explanation:

Hypothesis test about a population mean is done to evaluate two exclusive statements about a population in order to determine which is best supported by the sample data.

From the situations given, the correct options are

b. A recent study estimated that 20% of all college students in the United States smoke. The head of Health Services at Goodheart University suspects that the proportion of smokers may be lower there. This would require taking a sample and determining the probability of success.

c. A certain prescription allergy medicine is suppose to contain an average of 245 parts per million (ppm) of active ingredient. The manufacturer wants to check whether the mean concentration in a large shipment of pills is 245 ppm or not.

d. A report on the College Board website stated that in 2003 males scored generally higher than females on the SAT exam. An educational researcher wants to check whether this is true in her school district.

the reporter's right

step-by-step explanation:

1/4 = .25 / 25%

step-by-step explanation: so we look at the formula un = a + (n-1)d

un is the amount of seats

n is the nth term aka row number

a is the original sequence/row number

d is the difference between each term

so in this a=22 d=6 and n can remain as n because we are simply formjng a rule

lets put these in the equation

un=22+(n-1)(6)

this is your answer to part a

however

lets double check that this is correct, we'll try putting it into the second term

un=a+(n-1)d

u2=22+(2-1)(6)

u2=22+6

u2=28

as the question said the second row has 28 seats so now we know the formula we made is correct.

as for part b

un=a+(n-1)

its asking us to find a row with 100 seats.

remember un was the amount of seata so all we do is substitute this in.

un=100 a=22 d=6

un=a+(n-1)d

100=22+(n-1)(6)

so now we simplify to find n which is the row number.

100-22=22+(n-1)(6)-22

78=(n-1)(6)

78/6=(n-1)(6)/6

13=n-1

13+1=n-1+1

14=n

so now we know that in the 14th row there is 100 seats.

hope this and that you understood! its my first time using the app or anyone out on here : p its also me to revise so a bunch! ask more questions if you dont understand ☺