Introduction of Business Analytics

What purpose does the Price * Advertising column serve?

It is the interaction term we need it there is a chance that the relationship Between price and sales might change because of advertising

How do you get Excel to calculate regression line?

Make a scatter plot and add a trendline

Mean

This is the formula for the interval estimate of which population parameter

% of Grand Total

To get both joint and marginal probabilities in an Excel Pivot table, click on a numerical value, click "Show Values As" and click

In the probability table below, which value is a marginal probability? ​ Completed Obstacle Course Level No Yes Challenging 0.4 0.3 0.7 Easy 0.1 0.2 0.3 Total 0.5 0.5 1.0

0.5

A simple random sample of 100 students was asked, "Have you eaten pizza within the past week?" Of the 100 students, 82 said "yes." Calculate a 95% confidence interval for the true population proportion.

0.745<p< 0.895

A survey of 100 random high school students finds that 85 students watched the Super Bowl, 25 students watched the Stanley Cup Finals, and 20 students watched both games. How many students did not watch either game?

10

How do you display the regression equation and R squared in excel?

Right click on a datapoint-add a trend line-check boxes for equation and r squared

Sum of samples due to error

The _____ is a measure of the error that results from using the estimated regression equation to predict the values of the dependent variable in the sample.

Multicollinearity

The degree of correlation among independent variables in a regression model is called _____.

Residual

The difference between the observed value of the dependent variable and the value predicted using the estimated regression equation is known as the _____.

normal distribution

The distribution where the mean, mode, median are equal

pivot table

The excel feature we used to calculate joint and marginal probabilities

Correl- check for correlation

What command in Excel can you check for multicollinearity between independent variables in a regression

True or False

What is the difference in the Excel command for getting the probability mass function evaluated at a given value versus the cumulative probability up to the given value

NORM.DIST(40,000, MEAN, SD, TRUE) vs NORM.INV(0.1, MEAN,SD)

What is the main difference in the Excel commands for calculating the probability that a plane engine will last more than 40,000 hours and calculating the # of flight hours the bottom 10% of engines will reach

0.06 or 6.3

What is the probability that exactly 6 patients arrive during a given 15 min period?

Confidence level

When generating descriptive statistics using excel, what does Excel call the "Margin of Error" that you need to add and subtract to get the confidence interval?

Conditional Probability

When the probability of one event is dependent on whether some related event has already occurred.

Fast food restaurants pride themselves in being able to fill orders quickly. A study was done at a local fast food restaurant to determine how long it took customers to receive their order at the drive thru. It was discovered that the time it takes for orders to be filled is exponentially distributed with a mean of 1.5 minutes. What is the probability density function for the time it takes to fill an order?

f(x)= 2/3e ^-2/3x

All of the following are examples of discrete random variables except

time

u

A parameter is a numerical measure from a population, such as _____.

posterior probability

A probability that is a revision of a prior probability using additional information. A probability computed by Bayes Theorum

least squares method

A procedure for using sample data to find the estimated regression equation is _____.

Type 1 error

Error that occurs when a true when a true null hypothesis is rejected

RAND()

Function that generates a random number for cells in Excel

Upper tail test

H0: u greater than sign u0 Ha: u>u0 t= X-u0/sqrt s/sqrt n =1-T.DIST(t,n-1, TRUE)

multiple regression

Regression analysis involving one dependent variable and more than one independent variable is known as ____.

random experiment

is a process that generates well-defined outcomes.

A health conscious student faithfully wears a device that tracks his steps. Suppose that the distribution of the number of steps he takes in a day is normally distributed with a mean of 10,000 and a standard deviation of 1,500 steps. What percent of the days does he exceed 13,000 steps?

2.28%

In order to determine an interval for the mean of a population with unknown standard deviation, a sample of 24 items is selected. The mean of the sample is determined to be 20. The number of degrees of freedom for reading the t value is _____.

23

Scatter chart

A _____ is used to visualize sample data graphically and to draw preliminary conclusions about the possible relationship between the variables.

X=32

A pizza shop advertises that they deliver in 30 minutes or less or it is free. People who live in homes that are located on the opposite side of town believe it will take the pizza shop longer than 30 minutes to make and deliver the pizza. A random sample of 50 deliveries to homes across town was taken and the mean time was computed to be 32 minutes. What is the appropriate symbol to represent the value, 32?

H 0: u ≤ 30, Ha: u > 30

A pizza shop advertises that they deliver in 30 minutes or less or it is free. People who live in homes that are located on the opposite side of town believe it will take the pizza shop longer than 30 minutes to make and deliver the pizza. Write the null and alternative hypotheses that can be used to conduct a significance test.

1.2

A simple random sample of 100 observations was taken from a large population. The sample mean and the standard deviation were determined to be 80 and 12, respectively. Calculate the standard error of the mean.

H 0: p = 0.5, Ha: p not = 0.5

A student wants to determine if pennies are really fair when flipped, meaning equally likely to land heads up or tails up. He flips a random sample of 50 pennies and finds that 28 of them land heads up. If p denotes the true probability of a penny landing heads up when flipped, what are the appropriate null and alternative hypotheses?

discrete random variable

A variable that can take on specific numeric values such as number of tickets sold, marital status, population

Interval estimate

An estimate of a population parameter that provides an interval of values believed to contain the value of the parameter is known as the _____.

Unbiased estimator

An estimator where the expected value of the sample statistic is equal to the population parameter being estimated

prior probability

An initial estimate of the probability of events

Looking at this data what are 4 things you can use to choose the best model to estimate the relationship?

Be selective on independent variables -> use R squared -> use cross-validation->use hold out method

Mean

If a z-score is zero, then the corresponding x-value must be equal to the _____.

dependent variable

In a linear regression model, the variable that is being predicted or explained is known as _____. It is denoted by y and is often referred to as the response variable.

slope of the true regression line

In a simple linear regression model, y = ß0 + ß1x + ε the parameter ß1 represents the _____.

Become narrower

In interval estimation, as sample size became larger, the interval estimate

How do you check for violations of the conditions of the residuals in Excel?

In regression estimation you check the box for residuals. Then make a scatter chart of the residuals

y intercept

In the graph of the simple linear regression equation, the parameter ß0 represents the _____ of the true regression line.

Error term

In the simple linear regression model, the _____ accounts for the variability in the dependent variable that cannot be explained by the linear relationship between the variables.

Why does the formula "=2*(MIN(Lower Tail, Upper Tail)) give the p value for the 2 tail test?

Minimum determines the smaller tail and doubling gives you 2 tail test which test hypothesis for = or not equal

Sample space

all possible outcomes of the experiment

Prediction interval

an interval estimate of an individual y value given values of the independent variables

If the expected value of the sample statistic is equal to the population parameter being estimated, the sample statistic is said to _____.

be an unbiased estimator of the population parameter

As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution _____.

becomes smaller

Bayes' theorem is a method used to compute _____ probabilities.

posterior

An initial estimate of the probabilities of events is a _____ probability.

prior

A _____ describes the range and relative likelihood of all possible values for a random variable.

probability distribution for a random variable

A joint probability is the _____.

probability of the intersection of two events

Binomial Probability Distribution

used to describe many situations in which a fixed number (n) of repeated identical and independent trials has two, and only two, possible outcomes: Used to calculate the probability of a given number of successes in a set of (n) Bernoulli Trials