Question

Which method of gathering data is described by the statement, “You do manipulate variables”? Observed Study Experiment Simulation Indirect Study

Answer 1

Hint: In an observed study, you are not affecting the outcome of any variable since you are merely observing (it's like you are invisible and not even there)

Answer 2

Consider the experiment:
A consumer advocacy group is curious about the effectiveness of pain medication in treating migraine headaches. They randomly give different doses of aspirin, Tylenol, and ibuprofen to migraine sufferers. They then measure the results and compare.

What were the levels?

The migraine patients

The pain medication

The aspirin, Tylenol, and ibuprofen

The dosages of the drugs

This is dosages of the drugs right? thanks

Answer 3

@jim_thompson5910

Answer 4

that is correct

Answer 5

A mattress store boasts 4 out of 5 sleepers in a commercial that airs locally. I talked to the owner and found out he only talked to ten people.

The situation listed above is an example of what?

Regressive

Stratification

Variation

Replication

Blocking

Would stratification be right?

Answer 6

@jim_thompson5910

Answer 7

not sure on this one, one sec

Answer 8

you might be right, but I'm having a tough time verifying

Answer 9

Its, i will just go with it. thanks !!

Answer 10

np

Answer 11

@jim_thompson5910

For this is .512 right its just .8 * .8 * .8

A couple plans to have three children. The chance they have a girl is 0.8. The gender of one child is independent of the gender of another child. What is the probability of having all girls when having three children?

0.008

0.096

0.384

0.512

Answer 12

correct

Answer 13

A family wants to use a simulation to find out the probability of having at least one boy in their first three children. The digit assignment is even for a girl and odd for a boy. The random digits are given as: 2731472867829684178912. What is the correct information about the fourth family in this simulation?

The first born was a boy, followed by a girl, followed by a girl.

The first born was a girl, followed by a boy, followed by a girl.

The first born was a boy, followed by a boy, followed by a boy.

The first born was a boy, followed by a girl, followed by a boy.


Im very confused with this because it says even is girl, odd is boy. then the 4th family we are trying to find? how do we know which is the 4th family? if we just look at it the first number is even so its girl. so i went with the second answer

Answer 14

@jim_thompson5910

Answer 15

here's how I think of it

you have a set of numbers: 2731472867829684178912

these represent whether you have a girl or boy (even or odd)

if you break it up into groups of 3, you get: 273 147 286 782 968 417 891 2

the fourth family would be the block: 782

so that's odd, even, even, so you would get boy, girl, girl

Answer 16

not sure if that's correct or not since it's hard to confirm something like this

Answer 17

I think your right. i only have two more questions :)


From the five number summary 7 13 17 21 43 found after the class has taken the exam, which statement below is true?

The mean of the lowest 25% is 7.

25% of students earned 17 or fewer.

75% of students earned 17 or more.

The highest score in the class was a 43.

I got the third one 75 earned 17 or more is this correct?

Answer 18

@jim_thompson5910

Answer 19

17 is the median, which divides the data set into two halves (50% each)

Answer 20

the 5 number summary goes like this

min, Q1, median, Q3, max

Answer 21

so if 50% divides each set. the mean of the lowest would be 7? so the first one

Answer 22

since Q1 = 13

this means 75% of the class earned more than 13

Answer 23

7 is the min, so that's incorrect

Answer 24

so its not 75% earned more than 17. because if 75 earned more than 13 could we say 25% students earn 17 or fewer?

Answer 25

@jim_thompson5910

Answer 26

17 is the median

anything above it is 50%

anything below it is 50%

Answer 27

so 50% of the students scored higher than 17

50% of the students scored lower than 17

Answer 28

that's what it means to be the median

Answer 29

so the highest score is 43 is basically the only thing we can chose?

Answer 30

yes

Answer 31

max = 43

Answer 32

alright that was a little confusing for me aha. the last one i had was this

Answer 33

On the math portion of the SAT, the mean score was 510 with a standard deviation of 95. On the verbal portion, the mean score was 530 with a standard deviation of 85. We now know the mean of the combined score is 1040 with a standard deviation of 127.48. Given that these are normal distributions, we can do normal calculations with the combined statistics.

What score would you need in order to be in the top five percent?

1131.8

1197.7

1231.5

1249.7

Answer 34

i dont really know what to do to find the top 5%

Answer 35

@jim_thompson5910

Answer 36

one sec

Answer 37

unfortunately there's no other way but to use a calculator

Answer 38

I used this one

http://www.wolframalpha.com/input/?i=normalcdf&a=*C.normalcdf-_*Formula.dflt-&f2=1040&x=0&y=0&f=NormalProbabilities.mu_1040&f3=127.48&f=NormalProbabilities.sigma_127.48&f4=0.05&f=NormalProbabilities.pr_0.05&a=*FVarOpt.1-_***NormalProbabilities.pr--.***NormalProbabilities.z--.**NormalProbabilities.l-.*NormalProbabilities.r---.**NormalProbabilities.mu-.*NormalProbabilities.sigma---

Answer 39

on that page you'll see that P(z>1249.69) = 0.05

so this means that if you score higher than 1249.69, you are in the top 5%

Answer 40

Got it!! thanks so much for the help!!

Answer 41

yw