Lo 5

Inferences from means are more reliable with the standard deviation is large

False

Which of the following is the best measure of dispersion

Standard deviation

What does the notation below represents sum i=1 ^ n x i

Sum of the values of x starting at x1 and ending with xn

Which of the following is the correct formula for the variance of a population ?

Variance = mean difference squared / # of observations in population

Given a mean of 55 and a standard deviation of 10, what percent of observations will fall within 45 and 65. Assume a normal distribution.

68%

Using the following data points, what is the mean? 13, 18, 13, 14, 13, 16, 14, 21, 13

15

Given the following equation of a line, what is the intercept? Y = 75x ?

0

Given the data set k: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 What calculation does the notation below represent ? sum k = 1 to 15 k

1+2+3+4+5+6+7+8+9+10+11+12+13+; 14 + 15

Olly manages Hexton Hotel. The hotel incurs $30 of cleaning costs per customer and must pay $600 in utilities even if there are zero customers. Given the following equation, when Hexton Hotel has 15 customers , what are total expenses ? Y = 30X + 600

1,050

Given the following population , calculate the standard deviation . Round to two decimal places . 2,3,2,6,4,4,3,1,5,1,2

1.54

Tim works at a football stadium. The attendance at football games last year ranged from 50 to 300. Using his data, Tim came up with the following equation for estimating total revenue. Y=\$55x Using Tim's equation, what is total revenue when 250 people attend the football game ?

13,750

Using the following data points, what is the median? 13, 18, 13, 14, 13, 16, 14, 21, 13

14

Given the following population, calculate the variance. Round to two decimal places. 2,3,2,6,4,4,3,1,5,1,2

2.36

Given the following population , calculate the standard deviation . Round to two decimal places . 2,3,2,6,4,4,3,1,5,1,2

2.6

Assume a normal distribution95% of the observations in a sample fall between 400 and 500. What is the standard deviation?

25

Given the following data set, calculate the range. 10, 7, 9, 15, 11, 18, 27, 20, 22, 36, 33

29

Using the following data points, what is the median? 1, 2, 4, 9

3

Given the following data set, calculate the standard deviation of the sample. Use the variance rounded to the nearest whole number to calculate the standard deviation. Round your answer for the standard deviation to the nearest hundredth. 8, 11, 10, 4, 7, 5, 12, 15

3.74

Darius worked the following hours per week over the past month. Week 1 30 hours Week 2 35 hours Week 3 33 hours Week 4 40 hours Total 138 hours If Darius wants to calculate the average number of hours he worked per weekwhich of the following numbers would be used as the denominator?

4

Using the following data points, what is the mean? 1, 2, 4, 9

4

Assume a normal distribution. 68% of the observations in a sample fall between 400 and 500. What is the mean ?

450

Given the following data set, calculate the mean of the sample 8, 11, 10, 4, 7, 5,12,15

9

Given a mean of 55 and a standard deviation of 10, what percent of observations will fall within 35 and 75. Assume a normal distribution .

95%

What percent of observations will fall within 3 standard deviations from the mean?

99.7%

Which type of statistics is used to describe a data set?

Descriptive statistics

Julie is interested in the relationship between the number of hours she spent studying and her scores on the exams. To plot this relationship on a graph, what goes on the Y-axis?

Exam scores

What type of statistics is used to make predictions?

Inferential statistics

Given a mean of 78 and a standard deviation of 2, what is the likelihood that you would find observation of 85 in the sample ? Assume a normal distribution .

Less than 1%

Which of the following represents the average in a data set

Mean

W hich of the following is a descriptive statistic? Check all that apply .

Mean Median Mode

Which of the following terms represents the middle number in a data set sorted by numerical value?

Median

Which of the following terms represents the value that appears most often in a data set

Mode

A data set has the following descriptive statistics : Standard deviation 5 Mean = 3; Range = 10; Mode = 4 Which of the following statements is true regarding this data set?

Most of the observations fall within 5 points of the mean

Given options 1,2 & 3, which of the following is the mathematical notation for summation ? 1.Σ 3. f

Option 1

What is the formula for profit

Profit = Revenue - Expenses

Dr. Green would like to investigate the relationship between working the night shift and health issues. To conduct the study she will compare a sample of day shift employees to a sample of night shift employees . Which of the following participant selection strategies is best for limiting sampling bias ?

Randomly select participants for the study

How can the slope of a line be calculated?

Slope= change in y / change in x Slope= rise/run

In statistics, the terms sample and population are frequently used. The size of the sample is always

Smaller than the size of the population

When a linear relationship is plotted on a graph connecting the dots creates a

Straight line

At the point where the total revenue line intersects the total expenses

The company is breaking even

A large standard deviation implies that

The data is disbursed far from the mean

What is an advantage of calculating the median instead of the mean?

The median is not influenced by extreme data points

The slope of a line represents

The rate of change

Emma owns a toy store. If she wants to estimate the amount of revenue the company earns annually, what is the problem with selecting data points from November and December as the sample period? Select all that apply

The sample would overestimate revenue due to holiday sales The sample would not be representative of revenue throughout the year

A model perfectly explains the relationship between two variables

True

Sampling bias occurs when members of a population are systematically more likely to be selected in a sample than others

True

Which of the following represents how far away each point is from the mean

Variance

Which of the following descriptive statistics measure dispersion? Check all that apply .

Variance Range Standard deviation

The horizontal axis in a graph is referred to as the

X axis

The vertical axis of a graph is

Y axis

What is the equation of a line

y = mx + b m= the slope b = y-intercept