Business 212 - Statistics Practice Exam Pt.2

A basic concept of the binomial probability distribution is that it can be used for analyzing what specific kind of result?

A result that involves binary measurements.

What is the number of successes in a binomial experiment called?

Binomial random Variable

If we are computing standard deviation, when do we use n-1 degrees of freedom?

Dealing with a sample

Coefficient of determination?

Indicates how well a statistical model fits a data set.

Which of the following is TRUE about the coefficient of determination?

It is a quantity that indicates how well a statistical model fits a data set.

Which of these is an example of a calculation that Bayes' Theorem would be useful to find?

Likelihood of making a football team and becoming a starter

A coach records the levels of ability in martial arts of various kids. What type of data is this?

Ordinal (rank & order)

Suppose you toss three coins. What is the probability that you get two heads and one tail if the order in which you get them does not matter?

Probability 1/2. Toss three times 1/2x1/2x1/2=1/8 x3(two heads and one tail)=3/8

Probability Sample Non-probability Sample

Probability sample -chosen randomly Non-Prob sample - not chosen randomly

What type of data is best suited to a composite bar graph?

Sales data from multiple locations.

The Wilcoxon signed-rank test assumes:

Symmetry

Which statement about strategic decision-making using a payoff table is TRUE?

Tables will be inaccurate unless both internal and external influences are considered

Turtle Recovery has recognized an increase in turtles on the roadway. Each month the number of turtles recovered from being stranded on the roads has increased by 5%. The root cause has been linked to new construction in the lake region of the city. In March, the number of turtles rescued was 125. How many could the rescue team expect in May?

The formula for calculating the result of growth is the Prior Month Volume X Monthly Growth Rate raised to the number of months to be forecasted: 125 X 1.05 X 1.05 = 138.

Stratified random sampling works best when the researcher is familiar with the demographics of the population and:

The proportion of the demographics are important to the data being collected.

You perform an ANOVA and determine that the within-group variance is 89.9, while the between-group variance is 57.2. What can you concluded about this data?

There are no differences between the groups because there is more variance within the groups than between the groups.

What is the purpose for using a model in regression analysis?

To best fit the data

Find the correlation coefficient between the Average Number, what formula do you use

n(xy)-(x)(Y)/sq rt[n(x^2)-(x)^2][n(y^2)-(y)2]

Some high school students were divided into two groups, group A and group B, and given the same test. Group A consisted of 6 students and the average score was 12 with a standard deviation of 2. Group B consisted of 8 students and the average score was 11 with a standard deviation of 3. The variability within the groups is:

(2^2)/6 + (3^2)/8 = 0.667 + 1.125 = 1.792 Then, take the square root of this number to calculate the within group variability. Sqrt(1.792) = 1.339

What is the geometric mean of 2 and 4

2x4=8 sq rt = 2.828

8 different novels are to be placed side-by-side on a shelf. How many ways can the 8 novels be arranged on the shelf?

40,320 (8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 = 40,320 ways to arrange the novels).

What does a confidence interval of 95% actually mean?

95% of the time the average of the entire population should be in the average range of the sampled data.

purpose of a regression analysis?

Cut through extra data and irrelevant data in order to find the real relationship between two things.

In a regression, the _____ is the central variable that everything else is being compared to.

Dependent

Gary has a deck of 52 cards. He wants to know the probability of drawing the jack of spades and then drawing the two of hearts from the deck without replacing either card. What's the probability of this event? (A standard deck of 52 cards has 4 suits (hearts, clubs, spades, diamonds), each with 13 cards. Each suit has an ace, cards numbered 2 through 10, and a jack, a queen, and a king.)

The probability can be found by multiplying the probability of the first event (1/52) by the probability of the second event (1/51).

Kasey (a girl) and Michael (a boy) are auditioning for a reality TV show about singing. The show's producers want to choose one boy and one girl. Including Kasey and Michael, there are 4 girls and 2 boys auditioning. Is the event of Kasey being selected independent from the event of Michael being selected, or are the events dependent? Also, what is the probability that the producers will select Kasey and Michael for the show?

1/4 x 1/2 = 1/8 = 0.125.

What is statistical estimation?

Reducing errors in inferential statistics

The t-value is supposed to be _____.

greater than the value on the t-value table

Find the range for one standard deviation in the following data set: 16, 20, 14, 24, 16, 19, 30, and 8

find the variance by subtracting the mean (18.375) from each number, then squaring each of those numbers. Once that is finished, determine the average by adding them together and dividing by the total number of numbers. The variance is 38.35. To get the standard deviation find the square root of the variance. (SD = 6.2) To calculate this range, you will add and subtract the standard deviation to the mean. 18.375 ± 6.2. For this number set, you will get 12.175 to 24.575

In multiple regression analysis, collinearity refers to what situation?

Two independent variables have high correlation themselves

A manager has collected data that looks at how many bugs are in the programs his company produces each day. The company produces different numbers of programs each day, and some programs have several bugs. The best choice is for the manager to use a(n) _____ chart.

U

Jia has a sample size of 15. He wants to be able to make inferences about the entire population based on his work. What should he do when calculating his confidence interval?

Use t-table to compare calculations because this distribution uses fatter than normal tails under the normal curve to approx. the general population stand deviation.

The function STANDARDIZE requires which three data elements?

Value, Mean, Stand Deviation

Based on the central limit theorem application, which of the following statistical processes would not become easier to describe or analyze?

Relative variable importance

B'=

Represents all the set of elements that are not in B circle

Null hypothesis

Independent variable will have no effect on the dependent variable. There are no differences between the groups.

The _____ is the value of a sample statistic, which is used as an estimate of a population parameter.

Point estimate

Which of these is NOT a condition for using hypothesis testing for a proportion?

Population at least 10 times as big as the sample

Brian is conducting a study to determine whether meditation affects body weight. Brian plans to have three different groups, where each group will be assigned a different length of meditation time. When Brian gathers his data, he will compare the body weights of the participants between groups. Which type of ANOVA is Brian using?

Between subjects

A roulette wheel has 38 slots labeled with the numbers 1 through 36 and then 0 and 00. Slots 1 through 36 are colored either red or black. There are 18 red and 18 black. Slots 0 and 00 are colored green (see picture). On one spin of the roulette wheel, what is the probability that the ball lands on a red slot?

9/19 38 slots, 18 red = 18/38 Simplified to 9/19