QTM 1000 Final Exam

Which of the following can be reduced by ensuring that survey questions are clear and options are mutually exclusive?

measurement error

if two events are mutually exclusive and collectively exhaustive, what is the probability that one or the other occurs?

0.5

Requirements to use confidence interval for a proportion

1. np >/ 5 2. n(1-p) >/ 5

Events A & B are statistically independent if and only if:

P(AB) = P(A)P(B)

"or" probability question (formula)

P(AuB) = P(A) + P(B) - P(A ^ B)

conditional probability formula

P(result element/"given" element)/P("given" element)

How to calculate variance

SD^2

What must you remember to click when finding a proportion on minitab

"normal approximation"

Z-Score formula

(x1 - x)/SD

In a distribution with the first quartile (Q1) of -5 and the third quartile of (Q3) of 7, which of the following is considered an outlier?

-23.54

Borrowing, lending, and interest formula

F = P + I

general form of a piece-wise function

N(p) = 0, p < x int. of S(p) S(p), x int. of S(p) </ p < eq. price D(p), eq. price </ p < int. of D(p) 0, x int. of D(p) </ p

types of variables

Numerical: discrete (whole numbers) or continuous Categorical: nominal (no order) ordinal (order) Interval: no true zero Ratio: true zero

The width of each bar in a histogram corresponds to a:

difference between the boundaries of each class

The manager of the customer service division of an electronics retailer is conducting a survey of the customers. The possible response to the question, "What is your annual income rounded to the nearest thousands" is a:

discrete numerical variable

If P(A/B) = P(A), then events A and B are said to be

independent

Distribution Shapes

mean = median, symmetric median > mean, left skewed median < mean, right skewed

Trim dining hall sells hamburger sandwiches. On a typical weekday, the demand for burgers is normally distributed with a mean of 150 and standard deviation of 20. How many burgers must the restaurant stock to be 99% sure of not running out on a given day?

197

if the standard deviation of the sampling distribution of sample means is 5.5 for samples of size 36, then the population standard deviation must be

33

What is the coefficient of variation for a sample that with a mean of 260 and variance of 169?

5%

We're planning on conducting a survey on how many hours students use Facebook per week. Suppose we want to be able to say with 90% confidence that our estimate is off by less than 1 hour. We know the standard deviation of this variable is 1.5 hours. How many students should we survey?

7

Coefficient of variation formula

C of V = 100(SD/Mean)

If two events are collectively exhaustive, what is the probability that both occur at the same time?

Cannot be determined from the information given

Simple Interest Formula

F = P(1 + rt)

Suppose we get the following results from a regression analysis where we used "productivity" measured on a 0-100 scale as the dependent variable and "seniority" measured in years working at the company as the independent variable. Which choice is one of the correct interpretations where the intercept of the regression line is 96 and the slope of the regression line is -2.5?

For every additional year spent working at the company, the average productivity decreases by 2.5

Hypothesis tests for chi square test of independence

Ho: The two categorical variables are independent (there is no association) Ha: The two categorical variables are dependent (there is an association)

Total Interest Formula

I = Prt

Which of the following is most likely a parameter as opposed to a statistic?

The proportion of females registered to vote in a country

In conducting a hypothesis test, we are trying to make inferences about:

a population parameter

Generally speaking, if two variables are unrelated (as one increases, the other shows no pattern), the correlation will be

a positive or negative number close to 0

You have collected data on the approximate retail price (in $) and the energy cost per year (in $) of 25 TVs. Which of the following is the best for presenting the data?

a scatter plot

Compound Interest Formula

annually: F= P(1+r) ^t monthly: F= P(1+r/12) ^12t daily: F= P(1+r/365) ^365t

Calculating probability of single event on minitab

calc - probability distribution - binomial - input constant

The classification of student class designation (freshman, sophomore, junior, senior) is an example of a:

categorical variable

If you are constructing a confidence interval for mean of a population, the confidence interval will _____ with an increase in the sample size

decrease

the defining property of a simple random sample is that

every sample has the same chance of being chosen

A regression analysis between sales (in $1000) and advertising (in $) resulted in the following line: Y = -30 +5x. This implies that an increase of $1 in advertising is expected to result in a decrease of $25 in sales

false

In problems that we use chi-square test of independence for two categories, the null hypothesis is that "the two categorical variables are dependent"

false

true/false: if a null hypothesis about a population mean is rejected at the 0.02 level of significance, then it must also be rejected at the 0.01 level

false

In linear regression, the fitted value is the

predicted value of the dependent variable

Which of the following can be reduced by increasing the sample size?

sampling error

How to text chi-square association on Minitab

stat - tables - test for association *don't include totals*

This type of sampling method is used to ensure representation of subgroups of a population such as ethnicity?

stratified

The dean of students mailed a survey to a total of 400 students. The sample included 100 students randomly selected from each of the freshman, sophomore, junior, and senior classes on campus last term. What sampling method was used?

stratified sampling

Which of the following is not sensitive to extreme values?

the interquartile range

If we reject the null hypothesis, we conclude that:

there is enough statistical evidence to infer the alternative hypothesis is true

A type II error is when we do not reject the null hypothesis when the null is false

true

When samples of size n are drawn from a population, then the sampling distribution of the sample mean X is approximately normal, provided that n is reasonably large

true

A _____ determines how far a particular value is from the mean relative to the data set's standard deviation

z-score