Descriptive Statistics Review

These flashcards cover key concepts in descriptive statistics, including measures of central tendency, variability, distribution shapes, and graphical representation.

Descriptive statistics are used to characterize the shape, central tendency, and __ of a data set.

variability

A frequency distribution displays the number of times each score occurred or its __.

frequency (f)

N represents the total number of __ in a sample.

subjects

In a grouped frequency distribution, data may be organized into continuous ranges such as 95-100, 90-94, and __.

85-89

A __ is a bar graph that represents frequency distributions.

histogram

A line plot is also called a __ frequency polygon.

line plot

In a stem-and-leaf plot, the stem represents the __ part of the data while leaves are individual data points.

leading

A normal curve or bell curve indicates that most scores fall in the __ with fewer toward the extremes.

middle

A positive skew indicates that most scores cluster at the __ end of the distribution.

low

If a distribution is negatively skewed, most scores cluster at the __ end.

high

The three measures of central tendency are mean, __, and mode.

median

Mode is defined as the score that occurs most __ in a distribution.

frequently

The median represents the score at which there are as many scores __ it as above it.

below

The true average of a dataset is referred to as the __.

mean

The formula for calculating the mean involves dividing the sum of the scores by the __ of scores.

number

The __ is most affected by extreme scores in a distribution.

mean

In a negatively skewed distribution, the mean is pulled toward the __ of the distribution.

tail

The range of a set of scores is the difference between the __ and lowest values.

highest

Percentiles divide a dataset into __ equal portions.

100

The first quartile (Q1) is the same as the __ percentile.

25th

Interquartile range measures the distance between Q3 and Q1, representing the middle __ of the data.

50%

A box plot visually shows quartiles and the __ in a dataset.

range

The deviation score measures the distance each score is from the __.

mean

To calculate the sum of squares (SS), you square each deviation score and sum them; SS will always equal __.

0

In sampling, the sample variance is usually slightly lower than the true population __.

variance

The standard deviation is the square root of the __.

variance

A smaller standard deviation indicates less __ in scores.

variability

The coefficient of variation (CV) is expressed as a __.

percentage

The normal distribution has the mean, median, and mode at the __ value.

same

Z-scores express how many __ deviations a score is from the mean.

standard

T-scores compare bone mineral density to healthy adults aged __.

20-35 years

A T-score greater than __ indicates high bone mineral density (BMD).

1.0

Osteopenia is indicated by a T-score between __ and -1.0.

-2.5

The z-score formula is z = (X - __) / s.

mean

The median is the same as the __ percentile.

50th

A __ frequency distribution helps visualize data by grouping ranges.

grouped

In a right-skewed distribution, the long tail extends to the __.

right

The median is less affected by __ scores than the mean.

extreme

For sample variance, we divide sum of squares by __.

(n - 1)

In a normal distribution, approximately __% of scores fall within one standard deviation from the mean.

68.26

The area under the normal curve can be expressed in terms of __ scores.

z

The __ represents a theoretical concept with consistent characteristics in statistics.

normal curve

A score of -2.0 as a z-score indicates the score is __ deviations below the mean.

two

The __ plot visually represents distribution of scores at different intervals.

stem-and-leaf

The third quartile (Q3) is equivalent to the __ percentile.

75th

Bimodal distributions have __ modes.

two

Frequency distribution helps summarize how many times a particular score __.

occurs

The interquartile range (IQR) focuses on the __ of the data.

central 50%

Scores that fall below the first quartile can be described as being in the __.

lower 25% (or bottom quartile)

A standard deviation calculation helps in understanding the __ of data around the mean.

spread

The total number of subjects in a sample is denoted by __.

N

If all subjects have the same score, the range would be __.

zero

To evaluate variability, measures such as range, percentiles, and __ are used.

standard deviation

A boxplot includes whiskers that extend to the __ values in the data set.

highest and lowest

Scores significantly higher than the mean will inflate the __ value.

mean

The mean score can be influenced by __ scores, making it higher or lower than the median.

extreme

In a negatively skewed distribution, the tail points to the __.

left

In research, a high standard deviation suggests that scores are __ from the mean.

widely spread

When the mean, median, and mode are equal, the distribution is considered __.

normal

A grouped frequency distribution can summarize large amounts of __ efficiently.

data

Z-scores help standardize scores across __.

different scales

The concept of _ shows data's tendency towards certain values in a sample.

central tendency

Histogram bars show frequency counts of corresponding __ values.

data

Measures of variability include range, variance, and __.

standard deviation

In a box plot, the box represents the __ range of the data.

interquartile

In determining z-scores, a negative value indicates that the score is below the __.

mean