Bstats final

Other things being equal, as your level of confidence increases, the margin of error of a statistic

increases.

Which two scales of measurement can be either numeric or nonnumeric?

nominal and ordinal

Part 2: What is the standard error of the sample proportion?

.0265

If P(A) = .85, P(B) = .76, and P(A and B) = .72, then P(A | B) = _____.

.95

Results of a national survey showed that on average, adults sleep 6.9 hours per night. Assume hours of sleep follows a normal distribution with a standard deviation of 1.2 hours per night. Use the Empirical Rule to determine the proportion of adults who sleep less than 4.5 hours per night.

0.025

What is the probability that more than than 35% of the 300 students selected are Business majors? That is, find P(p-bar > 0.35)?

0.0294

AMR is a computer-consulting firm. The number of new clients that it has obtained each month has ranged from 0 to 6. The number of new clients has the probability distribution that is shown below. New clients, X : 0 1 2 3 4 5 6 P(X): 0.03 0.10 0.15 0.35 0.20 0.10 0.07 Part 1: What is the probability of gaining no more than two new clients in a given month?

0.28

Part 2: What is the probability of gaining at least 4 new clients in a given month?

0.37

Fifty-five percent of the applications received for a credit card are accepted. Let X = the number of applications accepted in a random sample of 12 credit card applications. Use the On-line Binomial Calculator or the distribution below: Part 1: Find the probability that more than half of the applications are accepted.

0.5270

According to the Ameriprise Financial Money Across Generations study indicate that parents are financially assisting their adult children with buying a car or buying a house. In January 2009, Money magazine reported that 54% of parents assisted their adult children in buying a car, 35% assisted in helping them to buy a house and 28% assisting them in buying both a house and a car. Suppose we select a family at random, what is the probability the parents assisted in buying a house or a car?

0.61

The average speed of cars traveling a particular stretch of a monitored highway is 66 mph with a standard deviation of 4 mph. Assume the distribution of speed of cars is Normal. What is the probability that a random car is traveling at a speed that is more than 64 mph?

0.8413

Americans eat about 20 teaspoons of sugar on average a day according to a report from the 2005-10 NHANES (National Health and Nutrition Examination Survey) database. Assume daily sugar consumption follows a normal distribution with a standard deviation of 5.0 teaspoons. What is the probability that a randomly selected American eats less than 28 teaspoons of sugar on average a day?

0.9452

Suppose the credit card company sampled 150 applications. Find the expected value of X.

82.50

Which one of the following conditions will result in a smaller margin of error for estimating a population mean?

A larger sample size, n

Generally, which of the following is the least appropriate measure of central tendency for a data set that contains outliers?

Mean

A numerical measure of linear association between two variables is the _____.

correlation coefficient

The summaries of data, which may be tabular, graphical, or numerical, are referred to as _____.

descriptive statistics

Part 3: Standard Error

.683

Part 4: Margin of error

1.359

Part 3: Calculate the expected value rounded to 2 decimal places.

3.17

What z-score corresponds to the lower 15% of any normal random variable?

-1.04

When using Excel to create a __________, one must edit the chart to remove the gaps between rectangles.

Histogram

The American Automobile Association (AAA) reported that families planning to travel over the Labor Day weekend would spend an average of $750 with a standard deviation of $200. Assume spending follows a Normal distribution. Use the Empirical Rule to determine the proportion of families planning to travel over Labor Day who will spend more than $950?

.16

On a December day, meteorologists have determined there is a 30% chance of snow, a 50% chance of a 'cold' day (below 20 degrees) and a 15% chance of both a 'cold' day and snow. What is the probability of getting snow given we have a 'cold' day?

.30

The student body of a large university consists of 30% Business majors. The university randomly selected 300 students to participate in a survey about proposed changes to the university meal plan. Part 1: What proportion of students randomly selected would you expect to be Business majors?

.30

Part 2: Find the probability that at least 3 of the applications are accepted.

0.9921

Part 2: critical value

1.989

An experiment consists of four outcomes with P( E 1) = .2, P( E 2) = .3, and P( E 3) = .4. The probability of outcome E 4 is _____.

100

Exhibit 2-1The numbers of hours worked (per week) by 400 statistics students are shown below. Number of Hours Frequency 0x10 20 10x20 80 20x30 200 30x40 100 Refer to Exhibit 2-1. The number of students working less than 20 hours is _____.

100

Researches in Georgia sampled 85 business students and asked them this question: "over the course of your lifetime, what is the maximum number of years you expect to work for any one employer?" The mean was computed to be 19.1 years with a sample standard deviation of 6.3 years. Construct a 95% confidence interval to estimate the mean maximum number years one expects to work for any one employer. Save this answer for the essay question following this matching question. Identify the following values necessary to construct a 95% confidence interval to estimate the mean maximum number of years one expects to work for any one employer. Part 1: point estimate

19.1

College students were surveyed to determine how much they planned to spend in various categories during the upcoming academic year. One category is the amount spent on school supplies. The graphs below show the amount of money spent on school supplies by women and men. Approximately what percent of women spend more than $105 on school supplies?

5%

Exhibit 2-4A survey of 400 college seniors resulted in the following crosstabulation regarding their undergraduate major and whether or not they plan to go to graduate school. Undergraduate Major Graduate School Business Engineering Other Total Yes 35 42 63 140 No 91 104 65 260 Total 126 146 128 400 ​Refer to Exhibit 2-4. What percentage of the students' undergraduate major is Engineering?

36.5%

The numbers of hours worked (per week) by 400 statistics students are shown below. Number of Hours Frequency 0x10 20 10x20 80 20x30 200 30x40 100 Refer to Exhibit 2-1. If a cumulative frequency distribution is developed for the above data, the last class will have a cumulative frequency of _____.

400

Suppose the credit card company sampled 150 applications. Find the standard deviation of X.

6.09

The weight of an object, measured in grams, is an example of _____.

a continuous random variable

Which of the following is NOT an example of descriptive statistics?

an estimate of the number of Alaska residents who have visited Canada

When the data are positively skewed, the mean will usually be _____.

greater than the median

The variance of a sample or a population cannot be _____.

negative

Income is an example of _____.

quantitative data

The height and weight are recorded by the school nurse for every student in a school. What type of graph would best display the relationship between height and weight?

scatter diagram

The sum of frequencies for all classes will always equal _____.

the number of elements in a data set

The standard deviation of a binomial random variable is

the square root of np(1-p

For a standard normal distribution, a negative value of z indicates _____

z is to the left of the mean.