What is the basis for the normal curve?
probability
What is the foundation of inferential statistics?
probability
Which of the following is a characteristic of the normal curve?
mean, median and mode are the same
Which of the following characteristics is associated with the "tails" of the normal curve?
asymptotic
Which of the following is another name for the normal curve?
bell shaped curve
What characteristic of the normal curve deals with skewness?
mean, median and mode
The fact that the tails of a normal distribution never touch the horizontal axis relates to the following property
asymptotic
If you fold a normal curve, each half would fit perfectly on top of the other. This characteristic is known as ___________.
symmetry
When we want to infer from a sample to the population, what assumption must be met?
population is normally distributed
Approximately what percent of scores fall between the mean and -1 to +1 standard deviations under the normal curve?
68%
Approximately, what percent of scores fall between the mean and -1 and -2 standard deviations under the normal curve?
14%
What type of standard score has M = 0 and SD = 1?
Z score
If you want to calculate a z score for a test where your raw score was 24, what other information must you know?
mean and standard deviation
If you know the z score, standard deviation(s) and mean (M), what formula would you use to compute the raw score (X)?
X=Z(s)+M
Which of the following is true of z scores that fall below the mean
they are negative
Which of the following is true of z-scores that fall above the mean?
they are positive
These types of values are most likely to be seen:
values very close to the mean
What are true of z-scores which are equal to the mean?
they are equal to zero
What percent of all scores fall below a z score of +1?
84%
What percent of all scores fall above a z score of +1?
16%
In statistics, the most common standard is to have at least this level of confidence:
95%
In a distribution with a mean of 100 and a standard deviation of 15, what is the probability that a score will be 115 or higher?
16%
What type of standard score is computed by multiplying the z score by 10 and adding 50?
T score
What is the standard used by statisticians to determine the probability of an event occurring outside of chance alone?
5%
If I flip a coin 10 times, how many possible combinations or outcomes could I have?
2(10)
If a z score of 1.65 included 45% of the area under the normal curve from the mean, what percent remains above 1.65 on the X axis?
5%
What is the z score for a raw score of 85 where the group mean is 75 and the standard deviation is 5?
2.0
If the null hypothesis claims that there is no difference between groups, it assumes the likelihood of this to be ____%.
100%
This is the most commonly used standard score:
Z score
To calculate a z-score, you:
subtract the mean from the raw score, and divide this difference by the standard deviation
Z-scores which fall below the mean will be:
negative
Z-scores which fall above the mean will be:
positive
A score that is three standard deviations above the mean would have a z-score of:
3
A score that is 2 1/2 standard deviations below the mean would have a z-score of:
-2.5
What is the T score for a z score of -1?
40
What is the T score for a z score of +3?
80
This percentage of scores fall within three standard deviations of the mean:
99.5%
This percentage of scores fall within one standard deviation of the mean
68%
This percentage of scores fall on either side of the distribution:
50%
If a distribution has a mean of 100 and a standard deviation of 15, what value would be +2 standard deviations from the mean?
130
If a distribution has a mean of 50 and a standard deviation of 5, what value would be -1 standard deviations from the mean?
45
If a distribution has a mean of 25 and a standard deviation of 2, what value would be -4 standard deviations from the mean?
17
If a distribution has a mean of 30 and a standard deviation of 5, how many standard deviations is 60 from the mean?
6
If a distribution has a mean of 50 and a standard deviation of 25, how many standard deviations is 0 from the mean?
-2
If a distribution has a mean of 1000 and a standard deviation of 100, how many standard deviations is 600 from the mean?
-4
The entire normal curve contains this percentage of scores:
100%
What two scores would divide a normal distribution such that 64.26% of the general population falls within them if the mean is 100 and the standard deviation is 15?
85 to 115
T scores and z scores are both considered what type of score?
standard score
The study of probability is the basis for determining the degree of confidence we have in stating that a particular finding or outcome is true.T/F
true
Algebra allows us to determine the exact mathematical likelihood that a difference between groups is due to practice or treatment as compared with chance or error.T/F
false
The normal curve has no skew.T/F
true
The normal curve is only sometimes symmetrical.T/F
false
Events that occur in the extremes of the normal curve have a very small probability of occurring.T/F
true
The percentages or areas under the normal curve can be interpreted as probabilities.T/F
true
Standard scores are raw scores which have been adjusted for the particular mean and standard deviation of the distribution from which they are derived.T/F
true
After conducting a statistical test, the calculated probability can be compared with a standard to see if the result is "significant." T/F
true
95% confidence corresponds with finding a z-score that has greater than a 5% chance of occurring.T/F
false
Critical z-scores depend on the mean and standard deviation of your particular distribution.T/F
false
Z-scores can be used to compare multiple distributions.T/F
true
Whether a z-score is positive or negative is of critical importance when using a z-table.T/F
false