Unit 6 statistics, Unit 5 statistics, unit 3

The least squares regression line will always pass through the coordinate:

(mean of x, mean of y)

Numbers 00-22 households with a system

12

Using the list of random numbers, with numbers 01-24 representing households with adults over 65, how many households need to be visited

33

Which of the following situations cannot be modeled by a binomial random variable?

Drawing 5 cards out of a deck of 52 and not replacing them and then counting the hearts

If x and y are independent random variables, E(x+y)=

E(x) + E(y)

The average value of a random variable over the long run of trials of some experiment is called the

Expected value

The "law of averages" applied to events in the short run is

Misconception

The law of averages applied to events in the short run is a(n)

Misconception

The correlation coefficient r is meaningless for ___.

bivariate data that is non-linear

If x is a geometric random variable with p=1/3, p(x<5), or achieving a success in four or fewer trials, can be calculated on a TI calculator using

geometcdf(1/3,4)

The correlation coefficient can only be calculated for two ___ variables:

quantitative

The statistic that describes the strength and direction of a linear association is:

r

This scatterplot might have correlation ___. (negative correlation)

r=-0.9

Which of the following is NOT a true statement regarding the correlation coefficient?

r>1 or r<-1

If we determine that r is strong r^2 is high, and s is small, we can conclude that ___.

the data may be linearly associated

For a set of bivariate data, x-bar for x= 5.25, x-bar for y=6.11, s for x=1.22, s for y=2.35 & r=0.7. The equation of this linear regression model is:

y-hat=1.35x-0.978

For a set of bivariate data, x-bar for x= 5.25, x-bar for y=6.11, s for x=1.22, s for y=2.35 & r=0.7. The y-intercept of the linear regression equation is:

-0.978

Using the Venn diagram, P(play sports or boys)=

.0751

Network preferences for an apartment building- what is the probability of of randomly selecting an apartment unit that has both internet and cable and is on the second floor?

.077

Network preferences for an apartment building- if we define A to be internet only and B to be 3rd floor connections, what is P(A and B)?

.094

P(play sports and boys)=

.253

Two-way table apartment network preferences. What is the probability of randomly selecting an apartment unit that has both internet and cable?

.359

Network preferences for an apartment building- if we define A to be internet only and B to be second floor connections, what is P(A u B)

.547

If x is a binomial random variable in an experiment with 5 trials, and in which p(success) = 0.3, p(x>3)=

0.031

X and y are independent random variables. If s for x is s= 0.212, and s for y is s = 0.322, then s^2 for x + y=

0.149

A researcher sends out 30 surveys. The probability a person returns the survey is 27%. If x is the number of surveys returned to the researcher, p(x>10)=

0.161

A branch of a tree diagram has two events: A = {completed homework} and B = {did not complete homework}. A and B are complements. If P(A) = 0.8, P(B) =

0.2

Katie is a 65% free throw shooter. If she shoots 15 free throws and x is the number of free throws made, p(x<9)=

0.245

X and y are independent random variables. If the standard deviation for x is s=0.212, and the standard deviation for y is s=0.322, then the standard deviation for x+y =

0.386

X is s=0.212, y is s=0.322: standard deviation for y-x =

0.386

Use this two way table to calculate: P(play sports/girl)

0.522

P(girl/do not play sports)

0.523

Senior class sports participation- P(play sports/boys)

0.528

The coefficient of determination= ___.

0.671

The coefficient determination is: (dependent variable is grade)

0.701

The value of the standard deviation is

0.707

The value of the variance is

0.707

Use this tree diagram to find the following probability: P(no school/snow)

0.8

The correlation coefficient= ___. (The regression equation: y=-5.22-13.11)

0.819

If x is a binomial random variable in an experiment with 5 trials, and in which p(success) = 0.3, p(x < = 3) =

0.969

Which of the following statements is NOT true about the correlation coefficient r?

0<r<1

The value of the mean is

1

In a binomial distribution, q=

1-p

For a set of bivariate data, x-bar for x= 5.25, x-bar for y=6.11, s for x=1.22, s for y=2.35 & r=0.7. The slope of the linear regression equation is:

1.35

The mean of this distribution is

1.4

For a set of bivariate data, x-bar for x= 5.25, x-bar for y=6.11, s for x=1.22, s for y=2.35 & r=0.7. The predicted value of y where x=2 is:

1.72

A dice is rolled three times, what is the probability of rolling a 5 every time

1/216

An experiment involves rolling a six-sided die. Let event A = the event of rolling an even number, and event B = the event of rolling a number less than or equal to 3. Then P(A/B)=

1/3

What is the probability of rolling a 3

1/5

A six-sided fair die is rolled five times. Each time the outcome is a four. The probability that the next roll will be a four is

1/6

A coin is tossed three times. What is the probability of getting exactly three heads?

1/8

The mean of a geometric random variable x is =

1/p

A fair trial has 8 outcomes, but on repeated trials one of the choices succeeds significantly more than the others. What is the probability of the trial?

12.5%

Using the list of random numbers, with numbers 00-34 representing households with a system, how many households would need to be visited?

17

Given this computer output, the standard deviation of the residuals is:

2.22

A fair coin is tossed 6 times each day and the number of heads is recorded. Over the long run, the average number of heads that occur each day will be

3

How many questions does the simulation predict will be answered correctly by guessing on each of a 20 question exam?

5

Simulation for successful serves during a volleyball player might have during a game. 60% success rate, 0-5 represent success , 6-9 represent no success. How many successes will there be in the first 12?

5

The equation of this least squares line is y-hat= ___. (regression line is y=5.22x-13.11)

5.22x-13.11

Which of the following is the binomial combination (5 3) NOT equivalent to?

60

The class average will now be=

75

P(play sports or boys)=

751

Simulation is performed to predict the number of times a 60% success rate volleyball player will successfully serve in a game where she serves 15 times. 1-12 represent success, 13-20 represent no success. 10 trials following results: 5, 9, 19, 12, 6, 11, 8, 17, 20, 13. How many successful serves out of 15?

9

A table is useful for calculating the variance of

A discrete random variable

The notation P(A/B) is read as the probability of

A given b

A random variable that can assume any uncountable, real number value is called a

Continuous random variable

An experiment involves rolling 1 six sided die. Event A = {roll an even number}, and event B = {roll a number less than or equal to 3}. Compare P(A|B) with P(A), and P(B|A) with P(B). Events A and B are:

Dependent

Mutually exclusive events are always

Dependent

In the conditional probability P(A/B), the condition is

Event b

The law of large numbers in probability states, over time, the

Experimental probability will approach the theoretical probability

Probability best describes what happens with random phenomena in

In the long run of an experiment

On one toss of a fair coin I obtain a head. The probability of obtaining a head on the next toss is still p = 0.5. This is because successive coin tosses are

Independent events

If you double each outcome value in a probability model, the standard deviation of the random variable

Is doubled

A binomial distribution will be approximately normally distributed if:

Np and nq are at least 10

If events A and B are independent, P(A and B) =

P(A) P(B)

If events A and B are independent, P(A and B)=

P(A)P(B)

Which of the following conditions are necessary to establish in order to say that A and B are independent events?

P(A/B)=P(A)

Which of the following formulas describes the probability distribution of the geometric random variable?

P(x) = (1-p)^x-1 P *formula A

A probability distribution table that lists outcomes paired with their associated probabilities is called a

Probability model

A simulation can be performed using which of the following devices to randomly chose an item?

Random number table

A variable that assumes numerical values associated with some random phenomenon is called a

Random variable

If you add a constant value to each outcome value in a probability model, the standard deviation of the random variable

Remains the same

Eight heads were obtained in eight tosses of a fair coin. The probability of obtaining a tail on the next toss is

Same as for the other tosses

Their concern is

Standard deviation will stay same

If you add a constant value to all values of a data set, that constant value affects

The mean only

Which of the following random variables would be an example of a discrete random variable?

The number of students in a school

If x is a geometric random variable with p=1/3, p(x=5) means:

The probability of the first success will occur in the 5th trial

Which of the following conditions is NOT a characteristic of a binomial random variable

Two outcomes are equally likely to occur

If x and y are independent random variables, Var(x+y)=

Var(x) + var(y)

Which of the following is NOT a characteristic of a binomial random variable x?

X is the number of trials until the first success in the experiment

Which of the following intervals best describes the values that r can assume? ([= inclusive, (=exclusive).

[-1, 1]

Which of the following conditions would signal that a linear model is NOT an appropriate model for bivariate data?

a pattern exists in the residual plot

An outlier on a scatterplot can occur with respect to the ___.

either the response variable or the explanatory variable or both

This residual plot indicates that a linear model ___. (x value is between 15-20 & y value is between 1-2)

is appropriate for this data

This residual plot indicates that a linear model ___. (u shaped graph)

is not appropriate for this data

The residual plot indicates that a linear model ___. (x value between 15-20 & y is between 2-3)

is not appropriate for this data.

The correlation coefficient...

is unitless

If the values of the response variable decrease as the values of the explanatory variable increase, we can conclude the relationship between these variables has ___.

negative direction

The scatterplot might have correlation ___. (positive correlation)

r=0.9

A residual plot is a ___.

scatterplot of the residuals against x

A graph that best describes the strength of the association between 2 quantitative variables is a ___.

scatterplot of the z-scores for each variable

A graph that describes the strength of the association between two quantitative variables is a ___.

scatterplot of the z-scores for each variable

For a set of bivariate data, x-bar for x= 5.25, x-bar for y=6.11, s for x=1.22, s for y=2.35 & r=0.7. For each additional increase in x, y increases by 1.35 is an interpretation of the:

slope

The variance of any discrete random variable is found by

summing the squared distance each outcome is from the mean times it's associated probability.

Two variables will have a strong association and a small correlation if:

the association is non-linear

The most accurate description of the strength of the association between two quantitative variables a scatterplot of:

the variables in terms of their standardized z-scores.