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Middle School Archive

Browse Middle School Statistics
Stars indicate particularly interesting answers or good places to begin browsing.

Selected answers to common questions:
    Graphs: bar graph, histogram, pictogram.
    Mean, median, mode, range.
    Statistics glossaries.
    Weighted averages.

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Calculating Average Starting Time [06/23/2003]

How do you average a series of starting times to get the average starting time? Say 9:30a.m., 10:15a.m., 11:45a.m., 1:30p.m., and 11:30a.m.

Grade and Test Averages [12/02/2001]

In a class of 21 students the average score on a math test was 77%. If Suzie got 95% and Jack got 78%, find the average grade of the other 19 students.

Mean, Median, Mode, Range [11/23/1997]

What are the definitions of mean, median, mode, and range?

Stem and Leaf and Scatter Plots [10/13/1998]

Information on stem and leaf plots and scatter plots.

Arithmetic vs. Geometric Mean [03/27/2001]

When is it appropriate to use the arithmetic mean, and when the geometric mean?

Average [05/10/2001]

Is it true that the average of a set of data is always computed by adding all the numbers together and dividing by the total number?

Average Wind Direction [05/21/1997]

Given a weather instrument that records wind direction, determine the average wind direction.

Averaging Ages [11/17/1999]

What is the average age of these 4 children...

Averaging Kelly's Test Scores [01/07/2002]

Kelly's average score on 4 tests is 85.5. The average of her 3 highest scores is 87, and her two lowest scores are the same as each other. What is the average of her two highest test scores?

Averaging Percentages [12/11/1998]

Why can you average percents in the usual way in some cases, and why do you have to use weighted averages in others?

Bar Graphs vs. Histograms [09/05/2002]

What is the difference between bar graphs and histograms?

Binomial Experiments [09/05/2003]

How can I explain the binomial distribution to my six grade math class?

Box and Whisker Plots [02/13/2000]

Can you explain how to make and use box and whisker plots?

Box and Whisker Plots [05/18/2000]

If there is an odd number of points in a data set, is the median considered to be part of the subgroup used to find the upper (or lower) quartile?

Calculating a Grade Average [08/15/1999]

How can I figure out my average if some things are worth more than others?

Calculating a Weighted Average Grade [05/05/2000]

What is the grade if the following make up the final grade: 45% = 3 tests (85, 78, 92), 25% = final (94), 15% = project (91.9), 15% = 3 case questions each worth 25 points (25, 25, 23.5)?

Calculating Percentage of Errors [03/21/2002]

You have items to be picked off a shelf every day. You pick one item a day and check it against the order. You wish to asign a percentage to the error in wrong items and/or number of items.

Can An Event Be Statistically Impossible? [06/19/2007]

How small must the probability be for an event to be statistically impossible?

Counting Techniques [12/29/1997]

Find the number of positive divisors of 17640, inclusive of 1 and 17640 itself. Find the number of odd integers between 2000 and 7000 that do not have repeated digits.

Data Set With Specified Mean, Median, Range [12/11/2003]

Make up a set of 5 numbers with a mean of 20, a median of 10, and a range of 50.

Defending the Mean [09/07/2003]

I know how to find the mean of a set of values, but can you explain why it's defined the way it is?

Defining Relative Error [03/11/2004]

I've seen "relative error" defined both as "the absolute error divided by the true measurement" and "the greatest possible error divided by the measurement itself." These definitions seem to be inconsistent. Which one is correct?

Definitions: Average, Mean, Mode [5/20/1996]

Arithmetic, geometric, harmonic means defined.

Definitions of Range [10/20/2003]

I can find only one definition of range in the math dictionaries - the difference between the smallest and the largest number in a set. We are always talking about 'They range in age from, or they range in height, or they range in weight, or they range in size, etc'. If the only defintion of range is the difference, why do we say 'They range...'?

Examples of Weighted Averages [03/26/2001]

Can you tell me what is meant by "weighted average," and give me some examples of when and how weighted averages are used?

Explaining Independent and Dependent Variables [10/25/2002]

Can you elaborate on the definitions of independent and dependent variables?

Explaining Weighted Averages [09/24/2002]

Can you please give me a layperson's explanation of why and how to use a weighted average?

Finding an Average without the Individual Numbers [09/12/2006]

A total of 50 juniors and seniors took a math test. The 35 juniors had an average score of 80 while the 15 seniors had an average score of 70. What was the average score of all 50 students who took the test?

Finding Average Times [02/15/2002]

My son and I have started a physical fitness program, and we are keeping track of our time for the mile. At the end of the week we would like to figure our average time.

Finding Mean, Median, Mode [03/29/1998]

Can you show me how to find the mean, median, mode, and range of a set of scores?

Frequency Table [09/17/2002]

How do I make a frequency table using temperatures and days of the week?

Frequency Table [10/13/2003]

What is a frequency table, and how do I make one?

Hairs on a Head [12/10/2002]

How many hairs are on your head?

Histogram [04/16/2001]

What is a histogram? What makes a histogram good?

How Do You Make a Circle Graph or Pie Chart? [12/16/2003]

I have some data on the weight of various parts of the human body. How do I turn that into a circle graph showing what percent of the total weight each part is?

How to Average [9/12/1996]

What is the average mass of 11.935g, 11.936g, 11.937g, and 11.938g?

Ice Skating Scoring [01/27/2001]

Why does the U.S. Figure Skating Championship use only five scores out of the seven given by judges?

Is There a Mode when All Data Points Occur Equally? [05/02/2007]

If you have a set of data such as {2, 15, 20, 39, 56, 67} is there a mode, and if so, what would it be?

Mean Less Than Median [08/17/2003]

Can you draw any valid conclusions about a set of data in which the mean is less than the median?

Mean, Median, and Mode [07/15/1998]

Can you explain the three ways to represent a group - mean, median, and mode? I am having trouble understanding the mode.

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