Question 93698This question is from textbook finite mathmatics
: 1) For the grouped data:
Score Frequency
90-100 8
80-89 12
70-79 26
60-69 14
An estimate of the mean is _____
2)The expected value of the following probability distribution is ___________.
xi 1 5 10 20 50
pi 0.30 0.40 0.10 0.15 0.05
3) Of 200 students surveyed 40 subscribe to Time Magazine, 65 subscribe to Sports Illustrated, and 10 subscribe to both. If a student is selected at random, what is the probability the student subscribes to Time Magazine or Sports Illustrated?
4) A consumer's group checked the gasoline mileage (to the nearest mile per gallon) on 25 different cars. The following gives a summary of the findings.
Miles per Gallon Frequency
Less than 15 2
16-20 4
21-30 13
31-40 5
Over 40 1
What quantities can be obtained from the table?
This question is from textbook finite mathmatics
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! 1) For the grouped data:
Score Frequency
90-100 8
80-89 12
70-79 26
60-69 14
An estimate of the mean is _____
Use the "mark" of each class as a representative value; multiply each
mark by its corresponding frequency; add the results; divide by the
sum of the frequencies to get the estimate of the mean:
8*95 + 12*84.5 + 26*74.5 + 14*64.5 = 4614
4614/60 = 76.9
=========================
2)The expected value of the following probability distribution is ___________.
xi 1 5 10 20 50
pi 0.30 0.40 0.10 0.15 0.05
Multiply each xi by its corresponding pi and add the results to get the expected value:
1*.3 + 5*.4 + 10*.1 + 20*.15 +50*.05 = 8.8
=========================
3) Of 200 students surveyed 40 subscribe to Time Magazine, 65 subscribe to Sports Illustrated, and 10 subscribe to both. If a student is selected at random, what is the probability the student subscribes to Time Magazine or Sports Illustrated?
P(T or S) = P(T) + P(S) - P(T and S)
= (40/200) + (65/200) - (10/200)
= 95/200
====================
4) A consumer's group checked the gasoline mileage (to the nearest mile per gallon) on 25 different cars. The following gives a summary of the findings.
Miles per Gallon Frequency
Less than 15....... 2
16-20 ..............4
21-30 .............13
31-40 ..............5
Over 40 ............1
What quantities can be obtained from the table?
An estimate of the mean; estimate of standard deviation; estimate of mode;
estimate of median; estimate of range; estimate of minimum; est. of maximum.
==============
Cheers,
Stan H.
|
|
|
