Question 1120348: I need all of these questions solved please I need help!!!
1.Find the area under the standard normal curve for the area between z = -2.33 and z = 2.33.
2.Find the area under the standard normal curve for the area to the right of z = -2.10.
3.In a recent year, a sample of grade 8 Washington State public school students taking a mathematics assessment test had a mean score of 281 with a standard deviation of 34.4. Possible test scores could range from 0 to 500. Assume that the scores are normally distributed.
Find the probability that a student had a score between 250 and 305.
4.In a recent year, a sample of grade 8 Washington State public school students taking a mathematics assessment test had a mean score of 281 with a standard deviation of 34.4. Possible test scores could range from 0 to 500. Assume that the scores are normally distributed.
Find the probability that a student had a score between 250 and 305.
5.From a pool of 25 candidates, the offices of president, vice-president, secretary, and treasurer must be filled. In how many ways can the offices be filled?
6.The access code for a cars security system consists of 4 digits. The first digit cannot be 0 and the last digit must be even. How many different codes are available?
7.The mean price from a sample of houses is $155,000, with a standard deviation of $15,000 and is normally distributed. Between what two prices do 95% of the houses fall?
8.The stretch in a spring varies directly as the attached weight. A 6kg weight stretches a spring 2.4 cm.
a. What is the constant of variation?
b. What weight would stretch the spring 4 cm?
9.Weekly salaries (in dollars) for a sample of registered nurses are listed.
774 446 1019 795 908 667 444 960
a. Find the mean, the median and the mode of the salaries. Which best describes a typical salary?
b. Find the range and standard deviation of the data set. Interpret the results in context of the real-life setting.
10.In a recent year, a sample of grade 8 Washington State public school students taking a mathematics assessment test had a mean score of 281 with a standard deviation of 34.4. Possible test scores could range from 0 to 500. Assume that the scores are normally distributed.
What percent of students had a test score that is greater than 250?
11.The volume of wood in a tree varies jointly as the height of the tree and the square of the distance around the tree trunk. If the volume of wood is 15.84 cubic feet when the height is 22 feet and the distance around the trunk is 3 feet, what is the volume of wood obtained from a tree that is 32 feet tall having a measurement of 4 feet around the trunk?
Select one:
a. 40.96 ft3
b. 32.96 ft3
c. 49.96 ft3
d. 44.96 ft3
12.The number of miles per gallon of gasoline that a vehicle averages varies inversely as the average speed the car travels. A vehicle gets 16 miles per gallon at 53 mph. How many miles per gallon will it get at 62 mph?
Select one:
a. 1.87 mpg
b. 13.7 mpg
c. 0.08 mpg
d. 18.7 mpg
Found 2 solutions by ikleyn, Boreal:
Answer by ikleyn(52779)   (Show Source):
You can put this solution on YOUR website! .
It is fine that you just learned how to "copy and paste".
But this forum works in other way.
It is NOT our goal to work instead of you and/or to substitute you in doing your job.
It is not our goal to serve industrialists who post tens of assignments in one mail.
Our goal is to teach the students in this forum.
Therefore, the RULE OF THIS FORUM is:
ONE and ONLY ONE problem per post
And one more notice:
From your post, I clearly see that you even do not read what you posted.
Otherwise, you'd notice that the problems #3 and #4 are the same.
Answer by Boreal(15235)  (Show Source):
You can put this solution on YOUR website! 1 The area from table or calculator is 0.9802 (probability)
2.To the right of z=-2.10 is 0.9821
3.Need the z score where z=(x-mean)/sd, so this is (250-281)/34.4 or -0.90. On the other side, 24/34.4 or 0.70. This area is 0.5740
11. V=k*h*d^2
15.84=k*22*9, so k=15.84/198 or 0.08 Use that in the next part.
v=0.08*32*16=40.96 ft^3.
a.
12.MPG=k/v
16=k/53
k=848
Use in next part
MPG=848/62 or 13.68
b.
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