Intro to Stat Questions

Question 2 (4 points)

A random sample of 25 customers was chosen in UMUC MiniMart between 3:00 and 4:00 PM on a Friday afternoon. The frequency distribution below shows the distribution for checkout time (in minutes).      

Complete the Frequency Table with the missing frequency and relative frequency numbers.

Enter answer for "A" with 2 decimal place acueacy.

Enter answer for "B" as an integer.

Enter answer for "C" as an integer.

Enter answer for "D" as an integer.

Enter answer for "E" with 2 decimal place acueacy.

Enter answer for "F" as an integer.

Question 3 options:

A random sample of 25 customers was chosen in UMUC MiniMart between 3:00 and 4:00 PM on a Friday afternoon. The frequency distribution below shows the distribution for checkout time (in minutes).

This is the same table from the previous question.      

What percentage of the checkout times was at least 3 minutes?

Enter answer as a percent without the percent sign to 0 decimal places.

Question 4 options:

A random sample of 25 customers was chosen in UMUC MiniMart between 3:00 and 4:00 PM on a Friday afternoon. The frequency distribution below shows the distribution for checkout time (in minutes).

This is the same table from the previous question with the Interval column added.            

In what class interval must the median lie?

Enter answer with the appropriate Interval number.

Question 5 (5 points)

Question 5 options:

A random sample of 25 customers was chosen in UMUC MiniMart between 3:00 and 4:00 PM on a Friday afternoon. The frequency distribution below shows the distribution for checkout time (in minutes).

This is the same table from the previous question.      

Assume that the largest observation in this dataset is 4.8. Suppose this observation were incorrectly recorded as 8.4 instead of 4.8.

Will the mean increase, decrease or remain the same? 

Enter

1    for Increase

2    for Decrease

3    for Remains the same  

Will the median increase, decrease or remain the same? 

Enter

1    for Increase

2    for Decrease

3    for Remains the same                                                                              

Question 6 options:

A 6-faced die is rolled two times.  Let A be the event that the outcome of the first roll is an even number, and B be the event that the outcome of the second roll is greater than 4.

How many outcomes are there in the sample space?

Enter answer as an Integer.

Question 7 options:

A 6-faced die is rolled two times.  Let A be the event that the outcome of the first roll is an even number, and B be the event that the outcome of the second roll is greater than 4.

What is the probability that the outcome of the second roll is greater than 4, given that the first roll is an even number?

Enter answer as a reduced fraction or a decimal rounded to 2 decimal places.                                                                                          

Question 8 options:

A 6-faced die is rolled two times.  Let A be the event that the outcome of the first roll is an even number, and B be the event that the outcome of the second roll is greater than 4.

Are A and B independent? 

Enter

Y for Yes

N for No                                                                          

Question 9 options:

The 5 number summary below shows the grade distribution of two Stat 200 quizzes.

Which quiz has less interquartile range in grade distribution?

a   Quiz 1

b   Quiz 2

c   Both quizzes have the same value requested.

d   It is impossible to tell using only the given information.

Answer the question by keying in the appropriate letter.                                                              

Question 10 options:

The 5 number summary below shows the grade distribution of two Stat 200 quizzes.

Which quiz has the greater percentage of students with grades of 90 or over?

a   Quiz 1

b   Quiz 2

c   Both quizzes have the same value requested.

d   It is impossible to tell using only the given information.

Answer the question by keying in the appropriate letter.                                                                           

Question 11 options:

The 5 number summary below shows the grade distribution of two Stat 200 quizzes.

Which quiz has lthe greatest number of students with grades less than 60?

a   Quiz 1

b   Quiz 2

c   Both quizzes have the same value requested.

d   It is impossible to tell using only the given information.

Answer the question by keying in the appropriate letter.                                                                           

Question 12 (10 points)

Question 12 options:

There are 1000 juniors in a college.

Among the 1000 juniors

200 students are taking STAT200

100 students are taking PSYC300

There are 80 students taking both courses.  

What is the probability that a randomly selected junior is taking at least one of these two courses?

Enter answer as a 2 place decimal or a reduced fraction. 

Question 13 options:

There are 1000 juniors in a college.

Among the 1000 juniors

200 students are taking STAT200

100 students are taking PSYC300

There are 80 students taking both courses.  

What is the probability that a randomly selected junior is taking PSYC300, given thathe/she is takingSTAT200?

Enter answer as a 1 place decimal or a reduced fraction.

Question 14 options:

The UMUC Stat Club is selecting three offices for the new year - a president, a vice president and a treasuer.

There are 10 qualified candidates.

How many different ways can the officers be selected?.

Question 15 (15 points)

Question 15 options:

Imagine you are in a game show. There are 6 prizes hidden on a game board with 10 spaces.

One prize is worth $100, another is worth $20, and four are worth $5.

You have to pay $20 to the host if your choice is not correct.

Let the random variable x be the winning.

What is your expected winning in this game?

Enter answer to 2 decimal places.

Determine the standard deviation of x.

Round answer to 2 decimal places.

Question 16 options:

Mimi just started her tennis class three weeks ago.

On average, she is able to return 30% of her opponent’s serves.

Assume her opponent serves 10 times.

Let X be the number of returns that Mimi gets.

As we know, the distribution of X is a binomial probability distribution.

What is the number of trials (n)?

Enter answer as an Integer.

What is the probability of success (p)?

Enter answer as a decimal to 2 place precision.

What is the probability of failure (q)?

Enter answer as a decimal to 2 place precision. 

Answer the three questions from left to right.                                          

Find the probability that that she returns at least 1 of the 10 serves from her opponent.

Enter answer to 3 decimal places

Do not enter answer as a percent.

How many serves can she expect to return?

Enter answer with 0 decimal paces. (integer)

Question 17 (10 points)

Question 17 options:

The heights of pecan trees are normaily distributed with a mean of 10 feet and a standard deviation of 2 feet.

What is the probability that a randomly selected pecan tree is between 10 and 12 feet tall.

Enter answer as a decimal rounded to 4 decimal places.

Question 18 (5 points)

Question 18 options:

The heights of pecan trees are normaily distributed with a mean of 10 feet and a standard deviation of 2 feet.

Find the 3rd quartile of the pecan tree height distribution.

Enter answer as a decimal rounded to 2 decimal places.

Question 19 (5 points)

Question 19 options:

The heights of pecan trees are normaily distributed with a mean of 10 feet and a standard deviation of 2 feet.

If a random sample of of 100 pecan trees is selected, what is the standard deviation of the sample mean, 

Enter answer as a 1 place decimal.

Question 20 (10 points)

Question 20 options:

A random sample of 225 statistic scores has a sample mean of 1500 hours.

Assume that the statistic scores have a population standard deviation of 300 hours.

Construct a 95% confidence interval estimate of the mean statistic scores.

Enter the lower and upper confidence limit numbers rounded to 0 decimal places. Enter the lower confidence interval number first.      

Question 21 (15 points)

Question 21 options:

Consider the hypothesis test given by                                   

Ho: p = 0.5 H1: p < 0.5

In a random sample of 225 subjects, the sample proportion is found to be phat = 0.53    

Determine the numerical value of the test statistic. (z)

Enter answer rounded to 3 decimal place.

Determine the p-value for this test.

Enter answer as a decimal rounded to 2 decimal points

Is there sufficient evidence to justify the rejection of Ho at an α = .01 level?

Enter Y for Yes Enter N for No

Question 22 (20 points)

Question 22 options:

Consumptions of a large amount of alcohol is known to increase reaction time.

To investigate the effects of small amounts of alcohol, reaction time was recoded for five individuals before and after 2 ounces of alcohol was consumed by each.

Does the data below suggest that the consumption of 2 ounces alcohol increase mean reaction time?

.

Assume we want to use a 0.10 significance level to test the claim.

Identify the null hypothesis and the alternative hypothesis. Enter the appropriate letter for the correct answer.

a     Ho:   There is no difference between reaction times before and after the alcohol consumption.

       H1:   There is a difference between reaction times before and after the alcohol consumption.

b     Ho:   There is a difference between reaction times before and after the alcohol consumption.

H1:   There is no difference between reaction times before and after the alcohol consumption.

c     Ho:   There is no difference between the test scores before and after the alcohol consumption.

H1:  The test scores after alcohol consumption are greater than the test scores before the alcohol consumption. 

d     Ho:   There is no difference between the test scores before and after the alcohol consumption.

H1:  The test scores after alcohol consumption are less than the test scores before the alcohol consumption.     

Determine the numerical value of the test statistic.

Round answer to 2 decimal places.)

Determine the p-value.

Round answer to 3 decimal places.

Is there sufficient evidence to support the  alternate hypothesis?

Enter 

Y for Yes

N for No

Question 23 (10 points)

Question 23 options:

A Stat 200 instructor is interested in whether there is any variation in the final grades between her two classes.

Data collected from the two classes are as follows:

Section 1         n1 = 31             x1 = 75             s1 = 12

Section 2         n1 = 30             x1 = 72             s1 = 14

Her null hypothesis and alternative hypothesis are:

H0:        σ1 = σ2           and      Ha:        σ1 < σ2

Determine the test statistic.

Round answer to 4 decimal places.

Determine the p-value for this test.

Enter P value rounded to 3 decimal places

Is there sufficient evidence to justify the rejection of the H0 at the α = .01 level.

Enter Y for yes.

Enter N for no.

Question 24 options:

A random sample of 4 professional athletes produced the following data where x is the number of endorsements the player has and y is the amount of money made (in millions of dollars).   

Find an equation of the least squares regression line.

Round each answer to 2 decimal place with the "constant" followed by the "slope".

Based on the above equation, what is the predicted value of y if x = 4?

Round answer to 1 decimal place.

Question 25 (15 points)

Question 25 options:

The UMUC Daily News reported that the color distribution for plain M&M's was:

40% brown

20% yellow

20% orange

10% green

10% tan

Each piece of candy in a random sample of 100 plain M&m's was clasified according to color, and the results are listed below:

Use a 0.05 significance level to test the claim that the published color distribution is correct.

Identify the null hypothesis by selecting the appropriate letter a or b.

a    The color distribution for plain M&M 's is not in agreement with what was reported the UMUC Daily News. b    The color distribution for plain M&M 's is in agreement with what was reported in the UMUC Daily News.

Identify the alternative hypothesis by selecting the appropriate letter c or d.

c    The color distribution for plain M&M 's is not in agreement with what was reported the UMUC Daily News. d    The color distribution for plain M&M 's is in agreement with what was reported in the UMUC Daily News.

Determine the test statistic. (What is the Chi Square value calculated from the data in the table)

Round answer to 1 decimal place.

Determine the Pvalue for this hypothesis test Round answer to 3 decimal places.

Is there sufficient evidence to support the claim that the published color distribution is correct??

Enter the appropriate letter for the correct answer.

a     The Ho hypothesis is rejected.  The Pvalue is less than the significance level,

b     The Ho hypothesis is not rejected.  The Pvalue is greater than than the significance level.