ADTA Study

Students tend to give more favorable responses towards the instructor because of his/her presence. The students' responses are influenced by the desire to please their instructor as that is the socially acceptable thing to do.

BIAS

What is NOT an example of analyzing the mean difference of two populations based on matched-pairs sampling?

Compare the mean wait time of customers being served at a bank before and after the weekend.

________ refers to data collected by recording a characteristic of many subjects at the same point in time, or without regard to differences in time.

Cross-sectional data

You would like to determine if there is a higher incidence of smoking among women than among men in a neighborhood. Let men and women be represented by populations 1 and 2, respectively. Which of the following hypotheses is relevant to this claim?

H0: p1 − p2 ≥ 0, HA: p1 − p2 < 0

Which data scales of measurement are associated with qualitative data?

Nominal and ordinal

If A and B are independent events, what is correct?

P(AB)=P(A)

It is known that the length of a certain product X is normally distributed with μ = 20 inches. How is the probability P(X > 16) related to P(X < 16)?

P(X > 16) is greater than P(X < 16).

What can be represented by a continuous random variable?

The average temperature in Tampa, Florida, during the month of July

What does not represent a continuous random variable?

The number of customer arrivals to a bank between 10 am and 11 am.

What is the purpose of calculating a confidence interval?

To provide a range of values that, with a certain measure of confidence, contains the population parameter of interest.

The union of two events, A∪B , is the event consisting of _______.

all outcomes in A OR B.

If the sampling distribution of X1¯−X2¯ cannot be assumed normal, we are unable to what?

compute a confidence interval .

A discrete random variable assumes a __________.

countable number of possible values

All F(df1,df2) distributions are positively skewed, where skewness depends on ________.

degrees of freedom

A value of estimator is called an _________

estimate

An ______ is the value of a statistic.

estimate

When a statistic is used to estimate a parameter, it is referred to as an _______.

estimator

A continuous random variable has the uniform distribution on the interval [a, b] if its probability density function f(x)

is constant for all x between a and b, and 0 otherwise

The random variable X follows the continuous uniform distribution if _________?

its probability density function is constant for all x between a and b, and 0 otherwise.

A statistic is taken from any sample drawn from the _________.

larger population.

As the df grow larger, the χ2df distribution approaches the normal distribution and becomes _____ ____.

less skewed

A hypothesis test regarding the population mean µ is based on the _______?

sampling distribution of the sample mean

The value of the test statistic for the hypothesis test of the population mean when the population standard deviation is unknown is computed as _________ The formula is valid only if X− approximately follows a normal distribution.

tdf=x− − μos/n√

Bias refers to the

tendency of a sample statistic to systematically over- or underestimate a population parameter

Two or more random samples are considered independent if

the process that generates one sample is completely separate from the process that generates the other sample.

In its standard form, Chebyshev's theorem provides a lower bound on

the proportion (or percentage) of observations lying within a certain interval

Nonresponse bias occurs when ______.

those responding to a survey or poll differ systematically from the nonrespondents.

A stacked column chart is a graphical method to summarize the relationship between what?

two categorical variables

Continuous random variable is characterized by ________.

uncountable values.

For any data set and k> 1, at least (1 − 1/k2)100% of observations lie where?

within k standard deviations from the mean

_____ table is used when the population standard deviation is known.

z

Always use the ________ when creating interval estimates for the population proportion. It is required, however, that the sample size be large enough for the normal approximation of the sample proportion.

z distribution

The intersection of events A = {apple pie, peach pie, pumpkin pie} and B = {cherry pie, blueberry pie, pumpkin pie} is ____________

{pumpkin pie}

For a given confidence level and population standard deviation, the bigger the sample size n, the _________ the confidence interval. Population size is not part of the formula to create a confidence interval.

narrower

As the df grow larger, the χ2df distribution approaches the ____ distribution and becomes less skewed.

normal

The formula for the confidence interval of the population variance σ2 is valid only when the random sample is drawn from a _____ distributed population.

normally

A binomial random variable is defined as the ___________

number of successes achieved in the n trials of a Bernoulli process.

Compared to nominal scale, the ________ scale reflects a stronger level of measurement. The order of the four scales is nominal, ordinal, interval, and ratio.

ordinal

All F(df1,df2) distributions are _____ skewed, where skewness depends on degrees of freedom df and df2.

positively

If the p-value for a hypothesis test is 0.027 and the chosen level of significance is α = 0.05, then the correct conclusion is to

reject the null hypothesis.

The probability that a normal random variable is less than its mean is

.5

The sum of the probabilities of any collection of exhaustive events must be _____.

1

How do you interpret the covariance between variables x and y?

A positive value of covariance indicates that, on average, if x is above its mean, then y tends to be above its mean.

For any value x of the random variable X, the cumulative distribution function is computed as _________.

F(x) = P(X ≤ x).

If we need to test if the mean of the first population is smaller than the mean of the second population, we should use

H0: µ1 - µ2 ≥ d0, HA: µ1 - µ2 < d0.

________ data relates to categories

Qualitative

________ data relates to numbers

Quantitative

______ table is used when the population standard deviation is unknown.

T

What can be represented by a discrete random variable?

The number of defective light bulbs in a sample of five

What is NOT an example of cross-sectional data?

The sales prices of single-family homes in Arizona collected since 2008.

_______ and _______ are the most widely used measures of dispersion.

Variance and standard deviation

A population is defined as ______?

all members of a specified group under study

The complement of an event A, within the sample space S, is the event consisting of ____________.

all outcomes in S that are not in A

For a given confidence level and population standard deviation, the ______ the sample size n, the narrower the confidence interval. Population size is not part of the formula to create a confidence interval.

bigger

Two (or more) random samples are considered independent if the process that generates one sample is ______ _____ to the process that generates the other sample.

completely unrelated

We use hypothesis testing to resolve conflicts between two competing hypotheses on a particular population parameter of interest, and these competing hypotheses are _______ ______.

mutually exclusive