24 - 25 - 27 statistics

Question 1

what is the mean?

Answer 1

the average

Question 2

what is the mean of this list of numbers: 5,6,2,2,2,7?

Answer 2

(5+6+2+2+2+7)/6 = 4

Question 3

what is the median

Answer 3

the number in the middle the list is in order

Question 4

what is the median of this list of numbers: 5,6,2,2,2,7?

Answer 4

the median is the average of the two middle numbers:
(2+5)/2 = 3.5

Question 5

what is the median of 1,2,3?

Answer 5

take half of 3 to get 1.5 and round it up to 2

Question 6

what is the median of 1,2,3,4?

Answer 6

the median is the average of the second and third numbers:
take half of 4 to get 2 and round 2 up to 3
these are the two numbers that contribute to the median.

Question 7

what is the mode?

Answer 7

the number that shows up the most often

Question 8

what is the mode of this list of numbers: 5,6,2,2,2,7?

Answer 8

it’s 2

Question 9

what is the range?

Answer 9

the difference between the biggest number in the list and the smallest number

Question 10

what is the range of this list of numbers: 5,6,2,2,2,7?

Answer 10

7 - 2 = 5

Question 11

define

what is the standard deviation?

Answer 11

a measure of how spread out a list of numbers is OR how much they deviate from the mean

Question 12

example

which has higher standard deviation: 5,6,2,2,2,7 OR 5,5,5,5,6,7?

Answer 12

5,6,2,2,2,7 ha shigher standarad deviation.

Question 13

define

what is an outlier?

Answer 13

an extreme data point that is far outside where most of the data lies

Question 14

function

how does an outlieraffect the average(mean), the range, and the median?

Answer 14

If an outlier is greater than the rest of the data, it increases the average (mean) and increasese the range since there is a larger gap between the minimun and the maximum. The median istypically unaffected.
outliers typically affect the mean but not the median

Question 15

technique

when dealing with average questions on the SAT,

Answer 15

think in terms of sums or totals

Question 16

technique

you can always find the sum by

Answer 16

multiplying the average with the number of subjects

Question 17

example

the higher the standard deviation,

Answer 17

the more spread out from the mean

Question 18

example

the lower the standard deviation,

Answer 18

the more clustered toward the mean

Question 19

recognizing type of questions: reading data

given graphs and charts to

Answer 19

interpret graphs

Question 20

confusing concept

maximum capacity of a truck=

Answer 20

maximum weight when reached maximum capacity - initial weight of truck when empty

Question 21

define/key formula

probability of a certain outcome

Answer 21

number in target group
/
number in group under consideration

Question 22

define

what is the goal of statistics

Answer 22

to be able to make predictions and estimations based on limited time and information

Question 23

technique

what is one common theme in statisctics and SAT questions?

Answer 23

using a sample mean to predict something about the entire population

Question 24

define

what is a confidence interval

Answer 24

the mean of your estimate plus and minus the variation in that estimate

Question 25

# example if the mean price of an apartment in Malden is $150,000 with a margin of error of $10,000, thi simplies that the true mean price of all apartments in Madlen is likely between $140,000 and $160,000. What is this interval known as?

Answer 25

Confidence interval

Question 26

# confusing concept the margin of error depends on two factors:

Answer 26

1. sample size 2. variability in data (often measured by standard deviation)

Question 27

# recognizing type of questions: "based on the design and results of the study, which of the following is an appropriate conclusion?"

Answer 27

association(correlation) vs. causation question

Question 28

# confusing concept True or False Because students who exercise get better exam scores than those who do not, the exercise *causes* an improvement in scores.

Answer 28

False - exercise is *associated* with improvement

Question 29

# confusing concept in order for researchers to see whether exercise does *cause* an improvement in exam scores, they must

Answer 29

they should implement random assignment; that is, instead of randomly selecting 200 students from one group who already exercise and 200 others that do not, they should have just randomly selected 400 students. Then randomly assign each student to exercise or not and see the difference in the two groups' performance

Question 30

# confusing concept * subjects not selected at random * subjects not randomly assigned Conclusions:

Answer 30

* results **cannot** be generalized to the population * cause and effect **cannot** be proven

Question 31

# confusing concept * subjects not selected at random * subjects randomly assigned

Answer 31

* results **cannot** be generalized to the population * cause and effect **can** be proven

Question 32

# confusing concepts * subjects tested at random * subjects not randomly assigned

Answer 32

* results **can** be generalized to the population * cause and effect **cannot** be proven

Question 33

# confusing concepts * subjects selected at random * subjects randomly assigned

Answer 33

* results can be generalized to the population * cause and effect can be proven

Question 34

# key idea if sample was **not** randomoly selected from the **general** population

Answer 34

it cannot make a generalization on the population

Question 35

# key idea if the subjects are **not** randomly assigned,

Answer 35

cause and effect relationship cannot be established

Question 36

# confusing concept True or False A confidence interval applies to an individual data point or group of data points.

Answer 36

False - a confidence interval applies only to the mean, which is a statistical measure, not an individual data point.

Question 37

# cofusing concept what does it mean in statistics to be 95% confidenct in something?

Answer 37

If the experiment were repeated again and again, each with 40 water samples, 95% of those experiments would give us a confidence interval that contains the true mean. So the 95% pertains to all the confidence intervals generated by repeated experiments, NOT the chance that any one confidence interval contains the true mean.

Question 38

# key formula Volume

Answer 38

Area of base x height

Question 39

# example volume of a cube

Answer 39

s^3

Question 40

# example volume of a rectangular prism

Answer 40

V = lwh

Question 41

# key formula volume of a cylinder

Answer 41

πr^2 h

Question 42

# key formula volume of a cone

Answer 42

1/3πr^2h

Question 43

# key formula volume of a sphere

Answer 43

4/3πr^3