stats exam 1

The square root of the ____(a)_____ is called the ____(b)_____ .

(a) variance (b) standard deviation

What is the z-score of a person whose LDL is one standard deviation above the mean?

1.0

The mean price of new homes from a sample of houses is $150,000 with a standard deviation of $15,000. If the price of a new home has a z-score of -2.5, what is the actual price of that new home?

112500

The 54th percentile in a large data set is 98.6. Approximately what percentage of the observations are greater than 98.6?

46%

Give the median of the following data set: 3 4 6 8 11 12

7

How would you type the equation "eight divided by six" in Excel?

= 8/6

stratified sampling

A type of probability sampling in which the population is divided into groups with a common attribute and a random sample is chosen within each group

The score made by a particular student on a national standardized exam is the 65th percentile. This means that

About 65% of all scores on the exam were lower than his.

Assume that the resting pulse rate for healthy adults follow a normal distribution with a mean of 69 beats per minute and a standard deviation of 9.5 beats per minute. Adam is told that the z-score of his pulse rate is -0.5. How should this statement be interpreted?

Adam's pulse rate is about one half of a standard deviation below average.

quantitative discrete data

All data that are the result of counting

ratio scale of measurement

All of the same in interval, except there is the addition of a true-zero point. Ex. height, weight, time on task, income, age

When is the mode most useful?

Categorical data

quantitative discrete data

Data that use numerical values to describe countable items ex. phone calls recieved in a day

cluster sampling

Divide the population area into sections (or clusters). Then randomly select some of those clusters. Now choose all members from selected clusters.

interval scale of measurement

Highest form of measurement and meets all of the rules of other forms of measurement: mutually exclusive categories, ordered ranks, equally spaced intervals, and a continuum of values. ex a degree outside

Is temperature in oC nominal, ordinal, interval, or ratio?

Interval

A geographer randomly selects twenty points in a county to study the elevation. One point is on a large hill while the other points are near water level. How does the mean compare to the median?

Mean > Median

A geographer randomly selects twenty points in a county to study the elevation. One point is on a large hill while the other points are near water level. What is the shape of the distribution?

Skewed right

A psychologist wants to study whether there is a correlation between sleep deprivation and the diagnosis of ADD in students. She randomly selects 20 students who are diagnosed with ADD and times how long they are asleep. She found the students slept, on average, six hours a night. What is the sample?

The 20 students studied

Which of the following is the symbol for sample mean?

___ x

Conveince Sample

a group chosen because of its ease of study

random sample

a sample that fairly represents a population because each member has an equal chance of inclusion

ordinal scale

a scale of measurement in which the measurement categories form a rank order along a continuum

The Department of Education wishes to estimate the proportion of all college students who have a job off-campus. It surveyed 1600 randomly selected students; 451 had such jobs. The population of interest to the Department of Education is:

all college students

Mean, median, and mode are all measures of the __________of a data set, while variance and standard deviation measure the ______of a data set.

center, spread

nominal scale

classifies data into distinct categories in which no ranking is implied

There are 7 sections of an introductory statistics course. A random sample of 3 sections is chosen, and all students in those sections are asked to fill out an evaluation of the text book. This is an example of

cluster sampling

Two students want to know how many parties people at their university attend per month. They ask 10 people that are in their statistics class how many parties they attend. This is an example of

convenience sampling

For any data set, half the data points are above the mean, and half are below.

false

A cop measures the speeds of drivers on a highway. The average speed is 70 mph. However, a truck is struggling to go uphill and is driving 50 mph. What can the cop say about their z - score?

it is negative

When a graph is skewed to the right

mean is greater than median

least affected by outliers

median

Is religious preference (i.e. Christian, Buddhist, Muslim, etc.) nominal, ordinal, interval, or ratio?

nominal

An observation that is radically different from the rest is called

outlier

Identify the following as either qualitative, quantitative discrete, or quantitative continuous: House numbers on a particular street

qualitative

Identify the following as either qualitative, quantitative discrete, or quantitative continuous: Body temperatures in oC

quantitative continuous

A student organization has 55 members. A table of random numbers is used to select a sample of 5. This is an example of

random sampling

The difference between the maximum and minimum value is called the

range

systematic sampling

select some starting point and then select every kth element in the population

All of the following are measures of central tendency EXCEPT: mode standard deviation median mean

standard dev

A university wants to find out how undergraduate students feel about on-campus food sources. They randomly select 10 Freshmen, 10 Sophomores, 10 Junior, and 10 Seniors to fill out a survey. This is an example of

stratified

The mathematics department wants to know how many hours a week students spend studying for math classes. They take the full list of students enrolled in math classes, and choose every 25th student from the list. This is an example of

systematic sampling

When a graph is skewed to the left

the mean is less than the median

A researcher wishes to estimate the average amount spent per person by visitors to a theme park. She takes a random sample of forty visitors and obtains an average of $28 per person. The population of interest is

visitors to the theme park.

Which of the following is the symbol for population mean?

𝜇

Which of the following is the symbol for population variance?

𝜎2