QM 214 Module 1 from Connect
The branch of statistics that summarizes important aspects of a data set is often referred to as ____________ statistics.
Descriptive
We generally divide the study of statistics into two branches: ____________ and _____________ statistics.
Descriptive and Inferential
Quartiles divide the data into ______ equal parts.
Four
The average of the absolute differences between the values of the data set and the mean is the
Mean Absolute Deviation
The _______________ is a measure of central location that divides the observations for a variable in half.
Median
The mean is usually less than the median when the data are _______________ skewed.
Negatively
The ____________ strategy recommends that observations with missing values be excluded from subsequent analysis.
Omission
Rating products from one to five stars generates ______ data.
Ordinal
The weakness with this scale of data is that we cannot interpret the difference between the ranked values because the actual numbers used are arbitrary.
Ordinal
The weakness with this scale of data is that we cannot interpret the difference between the ranked values because the actual numbers used are arbitrary.
Ordinal Scale
With this data, we are only able to both categorize and rank the data with respect to some characteristic or trait.
Ordinal scale
The range is the difference between?
The largest and smallest values
The function to find the mean of a subset in Excel is
AVERAGEIF
A qualitative variable is also known as a _____________ variable.
Categorical
With nominal data, you can
Categorize the data
The ______________ ______________ term relates to the way data tend to cluster around some middle or central value.
Central location
___________ and __________ are among the very first tasks most data analysts perform to gain a better understanding and insights into the data.
Counting and Sorting
Q4 percentile
100th
Q1 percentile
25th
The pth percentile divides a variable into two parts. What percentage is greater than p?
(100 - p)
Which of the following values is included in a box plot?
The first quartile
The steps to calculate the mean absolute deviation.
1. Calculate the arithmetic mean for the data set. 2. Find the absolute difference between each value and the mean. 3. Sum the absolute differences. 4. Divide by the sample (or the population) size.
Which of the following characteristics of interest is a variable? 1. The number of pizzas ordered from Pizza Hut per day. 2. The number of degrees in a circle. 3. The number of months in a year. 4. The number of letters in the English alphabet.
1. The number of pizzas ordered from Pizza Hut per day.
Which of the following is not a measure of central location? Median Mode Variance Mean Weighted mean
Variance
Which of the following is an example of descriptive statistics? 1. Test whether the average lifetime of all Brand A batteries exceeds 500 hours based on lifetime data from a sample of 20 Brand A batteries. 2. Conclude which of two brands of coffee is preferred by all coffee consumers based on taste test preferences of 200 coffee drinkers. 3. Calculate the percent of 2500 U.S. voters in an opinion poll who approve of the President's performance. 4. Estimate the percent of all U.S. voters who approve of the President's performance.
3. Calculate the percent of 2500 U.S. voters in an opinion poll who approve of the President's performance. Reason: Descriptive data often involves calculations of numerical measures. All other options involve inferential statistics due to the conclusion applying to ALL from the given data.
From the scenarios below, indicate the one that BEST reflects the nominal scale. 1. Note the ages of students in an undergraduate classroom. 2. Rank the service at a restaurant on a scale of 1 to 4. 3. Designate males as 0 and females as 1 to compare gender performance on an aptitude test. 4. Calculate the time it takes a worker to package a product for shipment.
3. Designate males as 0 and females as 1 to compare gender performance on an aptitude test.
If the median price for a home is $200,000, then ______ of the homes cost less than $200,000.
50%
Q2 percentile
50th
The median is also called the _____ percentile.
50th
Q3 percentile
75th
The interval scale of measurement
Allows for the use of negative values.
The ___________ _______ is the primary measure of central location.
Arithmetic mean
A ____________ helps us identify outliers and skewness in the distribution of a variable.
Boxplot
A box-and-whisker plot is another name for a
Boxplot
The ______________________ strategy recommends that the missing values be replaced with some reasonable imputed values.
Imputation
Which of the following statements about the mean absolute deviation (MAD) is MOST accurate?
MAD is denominated in the same units as the original data.
The __________________ is not considered a good measure of dispersion because it focuses solely on the extreme values and ignores every other observation in the sample or the population.
Range
The interval scale is less sophisticated than the ______ scale.
Ratio
____________ data allows us to review the range of values for each variable.
Sorting
The function to find the mean of a subset in R is _________________.
Tapply function in Excel
Which of the following values is included in a box plot?
The second quartile
The formula for the weighted mean is x bar =Σwixi. Using this formula, what is the restrictions on the weights.
They must sum to one.
True or false: The mean is the most widely used measure of central location for quantitative data.
True
A ______________ mean is used to calculate the mean of a frequency distribution.
Weighted
When a mean is calculated and some observations are given greater importance than others, we refer to this measure of central location as a ______.
Weighted mean
A skewness coefficient of _______________ indicates the observations are evenly distributed on both sides of the mean.
Zero