Stats HW Ch 3.1

A professor has recorded exam grades for 20 students in his class, but one of the greats is no longer readable. if the mean Score on the exam was 80 and the mean of the 19 readable scores is 84, what is the value Of the unreadable score?

So X divided by 20 equals 80. X is equal to 1600. However, X divided by 19 equals 84. X equals 1596. The unreadable score is the difference between the two. 1600-1596 is equal to four. That is The unreadable score

On a class survey, students were asked to estimate the number of times a week, on average, that they read a daily newspaper. A. is this variable continuous or discrete? B. The histogram shows the results of this variable when the survey was administered to a class of 36 college students. B.what is the minimum responses? C. Maximum number of responses? D. How many students did not read a newspaper at all? E. What is the mode? F. Describe the shape of the distribution

A. Discreet because the value for each person would be a whole number B. O C. 6 D. 1 E. 5 times F. Unimodal and skewed to the left

Suppose you have scores of 60, 70, 65, and 60 on quizzes in a class. What is the meaning of the scores? What score would you need on the next quiz to get an overall meaning of a 65. If the maximum score on a quiz is 90 is it possible to have a mean of 70 after the fifth quiz?

A. The mean is 63.75. Add them all up and divide by the number of values B. On the next quiz you need a score of a 70to bring it to a mean of 65. The way you do this is you add all the scores together which is 255+ X. Now you have To divide that entire number by five and that equals 65. Multiply 65 by 5 to get 325. Now subtract 255 from 365 and X equals 70. C.No it's not possible because 255+ and 90, divided by five, equals 69. Period

What does the mu symbol stand for

Population mean

Find the population mean or sample mean as indicated. Population: nine, three, 18, 11, 19

Choose the mu symbol for population. It looks like a pea. Add up 9+3+18+11+19 = 60 divided by the number of variables 12345 variables equals 12

True or false: When an observation that is much larger than the rest of the data is added to the data set, the value of the median will increase substantially?

False

True or false: a dataset will always have exactly one mode?

False. The mode of a variable is the most frequent observation of the variable that occurs in the data set. To find the mode, tally the number of observations that occur for each data value. The data value that occurs most often is the mode. A set of data can have no mode, one mode, or more than one mode. If no observation occurs more than once, then the dad has no mode.

When an observation that is much larger than the rest of the data is added to the data set, the value of the mean will what?

Increase

When you are looking at a distribution that is skewed, where can you find the mean median and mode?

Mean is always at the bottom, then median, and mode at the highest

What is the difference between the symbols capital N and n ?

N Represents a population size and n represents a sample size

What symbol is used for the sample mean?

The X with the line over it

What symbol is used for summation?

The capital E

According to a study, the median household income was 51,768 for one group. And 33,223 for another group. The main for each group was 65,924 and, 44,024 respectively. Does this suggest that the distribution of household income for each group is symmetric, skewed to the right, or to the left?

The fact that the mean is larger than the median for each group indicates that there are extremely large incomes that are affecting the mean. So the shape is skewed to the right. Because although the majority of the medians are smaller on the left side, the larger amounts trail it to the right.

An insurance company crashed for cars on the same model at 5 mph. The cost of repair for each of the four crashes was 417, 413, 452, and $215. Compute the mean, median, and mode cost of repair.

The mean cost of repair is 417+413+452+215 = 1497. Now divide that by four which equals $374.25 The median cost of repair is 415. This is because the median is shared by two numbers 413 and 417. You add them up and divide by two. The mode does not exist because no number is used more frequently than another.

Mr. Adkins finds that the mean height of all 14 students in his class is 67 inches. But, shortly afterwards, Danny walks in late. He is 68.5 inches tall. What is the mean height of the 15 students in the class

The mean height is 67.1 inches tall.

A histogram of a set of data indicates that the distribution of the data is skewed right. Which measure of the central tendency will likely be larger, the meeting or the median?

The mean will likely be larger because the extreme values in the right tail tend to pull the mean in the direction of the tail

Which measure of central tendency best describes the center of the distribution?

The median

Which of the following sentences is a description of the median of a data set for a variable?

The median is the data value that lies in the middle of the data when the data is arranged in ascending order

Find the population mean or sample mean as indicated. Sample: 25, 16, one, six, 17

To find the sample mean, since it says sample, choose the X with the line over it for sample, and then add up all the numbers 25+16+1+6+17 equals number, divided by the number of variables in the sample Which is five. And that gives you 13

Determine whether the statement is true or false. The mean is the measure of central tendency most likely to be affected by an extreme value/outlier?

True. The mean is the measure of central tendency most likely to be affected by an extreme outlier because the outlier will affect the sum of the data values.

True or false: a dataset can have the same mean median and mode.

True. The mean of a data set is the sum of the data entries divided by the number of data entries. The median of a data set is the value that lies in the middle of the data when the data is ordered. The mode of a data set is the data entry that occurs most often in the greatest frequency. When a distribution is symmetric and unimodal, the mean, frequency, and mowed or equal