Biostats Test 1 Review

To compute population variance, the value of SS is divided by?

N

For Following Scores: X F 5 1 4 1 3 4 2 2 1 2 How many individual scores are in the entire set?

N= 10

A researcher is curious about the IQ of registered voters in the state of Florida. The entire group of registered voters in Florida is an example of a?

Population

For a population of u= 80 and o= 12, the z-score corresponding to X= 74 is z= ?

-.50 (74-80 divided by 12)

A normal distribution has μ=100 and σ=20. What is the probability of randomly selecting a score less than 130 from this distribution?

.9332

If all n= 10 individuals in a sample have exactly the same score, then the sample standard deviation will have a value of ________?

0

A vertical line is drawn through a normal distribution at z=1.00. the proportion of the distribution that is located between the mean and the line is?

0.3413

What proportion of the score in a normal distribution have a z-score less than z=0.86?

0.8015

In a population of N= 10 scores, the smallest score is X= 8, and the largest score is X= 20. The ________ is the population is?

13

For Following Scores: X F 5 1 4 1 3 4 2 2 1 2 How many individuals had a score of X= 5?

2

For the following scores, was is ∑X^2? Scores: 2, 0, 4, 2

24 (sum of scores x # of scores)

A population of N= 10 scores has u= 50 and o= 5. What is the population variance?

25

For Following Scores: X F 5 1 4 1 3 4 2 2 1 2 For this distribution, what is the value of ∑X?

27

A population of N= 5 score has SS= 40. What is the variance for this population?

40/5= 8

What are the real limits for a score of 50?

49.5 and 50.5

What is the median for the following set of scores? Scores: 1, 4, 6, 17

5

For any normal distribution, the probability of selecting a score greater than the mean is_______?

50%

For a population with μ=60 and σ=8, what is the x value corresponding to z=1.50? for 5 points draw the normal curve at the bottom of the page level the locations of μ, σ, and shade in the area corresponding to z<1.50

72

Statistical methods that use sample data to answer general questions about a population are called?

Inferential Statistics

What is the value of SS for the following sample? Scores: 1, 3, 5

SS= 8 (# of scores - each score= SS)

Which of the following samples identifies the sample variance?

S^2

A researcher is interest in American college students. A group of 50 students in interviewed and the research finds that the these students sleep an average of 6.7 hours per day. For this study, the students are an example of a?

Sample

The variability of the scores in a sample tends to be _______ the variability of of the scores in the population from the sample was obtained?

Smaller than

In general, what is the relationship between the standard deviation and the variance?

Standard deviation is the square root of variance.

The symbol of SS stands for?

Sum of squared deviation scores

A teacher gave a reading test to a class of 5th-grade students and computed the mean, median, and mode for the test scores. Which of the following statements cannot be a accurate description of the scores?

The majority of students had scores above the median. IS NOT ACCURATE.

For a normal distribution with μ=60 with σ=8, the probability of selecting a score greater than x=64 is equal to__________?

The proportion of the distribution with z-scores greater than 0.50.

A population has a mean of M= 30. If one score with the value of X= 10 is removed from the sample, what effect will this (size) have on the sample mean?

The sample mean will increase.

For a population with u= 100 and o= 20, the X value corresponding to z= 1.50 is?

X= 130 (1.50 x 100 +20)

In a normal distribution, what z-score value separates the highest 20% of the scores from the rest of the distribution?

Z= 0.84

A z-score of z= -2.00 indicates a position in a distribution ______?

below the mean by a distance equal to 2 standard deviations.

Which set of scores has the least amount of variability? a. 11, 17, 31, 53 b. 5, 11, 42, 22 c. 145, 142, 145, 147 d. 27, 105, 10, 80

c. 145, 143, 145, 147

Which of the following is true of a symmetrical distribution? a. the mean, median, and mode are all equal b. mean = median c. mean = mode d. median = mode

a. the mean, median, and mode are all equal

Which of the following is NOT a continuous variable? a. time to solve a problem b. temperature c. height d. number of children in a family

d. number of children in a family

In an experiment, the researcher manipulates the ______ variable and measures changes in the ________ variable.

independent, dependent

A researcher measures personality of for a sample of n= 50 people and classifies each person as either Type A, Type B, or Type C personality. Which measure of central tendency would be appropriate to summarize these measurements?

mode

To compute sample variance, the value of SS is divided by?

n-1

On an exam with a mean of u= 70, you have a score of X= 75. Which of the following values for the standard deviation would give you the highest position within the class?

o= 1

After measuring a set of individuals, a research finds that Bob's score is three times greater than Jane's score. These measurements must come from an ________ study?

ordinal

Although research questions typically concern a ______________, a research study typically examines a ____________?

population, sample

Determining a person's age would involve measurement on a _________ scale of measurement?

ratio

Although samples are usually representatives of the population from which they are selected, you should not expect a sample statistic to be exactly equal to the corresponding population parameter. The natural differences that exist between statistics and their parameters are known as?

sampling error

A resent study reports that increased lighting during the winter months result in lower depression scores. In this study, what is the dependent variable?

the level of depression

A research is measuring problem-solving time for a sample of n= 20 children. However, one of the children fails to solve one problem so the research has an undetermined score. What is the best used central tendency for this data?

the median

A population of N= 4 scores has SS= 12. What is the standard deviation for this population?

the square root of 3

A recent study reports that infant rats fed a special protein-enriched diet reached an adult weight 10% greater than litter-mates raised on a regular diet. For this study, what is the independent variable?

type of diet given to the rats