Ask Dr. Math

High School Archive

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

Selected answers to common questions:
    Mean, median, mode, range.
    Statistics glossaries.
    Weighted averages.

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Origin of Ogive [08/26/2002]

What is the origin of the term 'ogive'?

Outliers [03/14/2001]

What is the definition of an outlier?

Outliers in a Box-And-Whisker Plot [12/07/2000]

Would a point that is exactly 1.5 times the IQR away from the inner or outer quartiles be considered an outlier?

Pareto and Bar Charts [3/12/1997]

What are three distinguishing differences between Pareto Charts and Bar Charts?

Percentage Less than a Given Value [11/22/1997]

If some data are normally distributed, and I know the mean and the standard deviation, how do I find out what percentage of the sample is less than (or greater than) a given value?

Pi and Probability [12/21/1997]

I'm doing a report for my math class on the relation between pi and probability...

Poisson as a Limit to a Binomial Distribution [05/29/2000]

How do I prove that the limit of a binomial distribution with large n and small p is a Poisson distribution?

Population Densities [03/17/2002]

Given population data, how many people would have to move from Connecticut to Wyoming to make the population densities the same?

Potential Limitations of ANOVA Testing [11/13/2005]

Are there any drawbacks or problems with the information reported by use of the ANOVA test in statistics?

The Power of a Statistical Test [02/11/1999]

How do you find the power of a test, given the significance level?

Proof of Bernoulli's Law [6/22/1996]

I would like to know how one can prove Bernoulli's law of large numbers

Proof of Normal Distribution [10/15/1997]

Can you explain (and prove) why samples taken from a normally distributed population will also be normally distributed?

Quadratic Interpolation [03/27/2003]

How do I come up with this polynomial? y = [(x - x2)(x - x3)]/[(x1 - x2)(x1 - x3)]*y1 + [(x - x1)(x - x3)]/[(x2 - x1)(x2 - x3)]*y2 + [(x - x1)(x - x2)]/ [(x3 - x1)(x3 - x2)]*y3.

Quartiles and Interquartile Range [10/27/1999]

What is interquartile range? How do you calculate Q1, Q2, and Q3?

Randbin [03/14/1999]

Consider an airplane that has 113 seats... what is the probability that at most 113 will check in?

Random and Pseudorandom Numbers [10/13/1998]

When are the numbers of a sequence truly random numbers and not pseudorandom?

Random and Systematic Errors [03/05/2002]

What are 'random errors' and 'systematic errors'?

Range - Difference or Difference + 1? [08/05/2003]

Is range the same as 'difference' or not?

Range, Mean, Median, and Mode [11/17/1998]

Why do we study range, mean, median, and mode? How will these concepts help me in real life?

Rating Ski Slopes [02/07/1999]

Can you help me rate the best ski slope value, based on data that I've collected?

Ratioing Errors [01/07/2002]

How do you calculate the error bars for ratios?

Re-Calculating the Standard Deviation [03/20/2002]

How can I re-calculate the standard deviation of a set of values when I insert a new value but I don't know what the existing values are?

Regional Marathon Problem [1/9/1995]

Those wanting to participate in a state marathon race must first qualify by running in a regional marathon...If there are to be only 600 runners in the state marathon, what is the slowest time that will qualify a regional runner for the state race?

Regression Method [11/18/1997]

What is the regression method?

Representing the Average [08/18/1998]

Suppose a, b, and c represent one student's scores on three math tests. Write an expression for the students' average if: a) all three tests count equally; b) the last counts as if it were two.

Rolling a Die 600 and 5000 Times [06/03/2001]

Toss a die 600 times, 5000 times. How many times does each number come up? Approximately how many would you expect?

Runs Batted In and Earned Run Average [10/26/2000]

How do you calculate RBI for a player on a baseball team? Also, how do you find a pitcher's ERA?

Sample Variance [08/08/1997]

Could you help me understand the sample variance using the data 4,5,2,6,4,3,4 where n = 7 and X = 3.52?

Scaling Test Scores [09/28/1997]

How do professors and teachers use standard deviation to scale scores?

Several Probability and Statistics Techniques [04/13/1998]

Examples of binomial distribution, Poisson distribution, significance test, and calculation of confidence interval.

Significance of Handwashing Frequency [02/23/2002]

I need to determine whether the absence of an observer makes a statistically significant difference. I think I need to use a chi- squared test...

Significant Difference? [05/08/1999]

A research question: does mean delivery time differ for boy babies and girl babies?

Simpson's Paradox [02/27/2002]

What exactly is Simpson's Paradox (a.k.a. Stein's Paradox)?

Spearman Rank Correlation Coefficient [08/26/1997]

I would like to get a clear definition of Spearman's Rank and how it is used.

Spearman's Rank Correlation [02/17/1999]

Where does the 6 in the formula of Spearman's rank correlation come from?

Standard Deviation [07/05/1997]

Given the average height of a group of students and the standard deviation, find the percentage of students who are taller or shorter than the average.

Standard Deviation [05/17/1999]

What is standard deviation?

Standard Deviation and Conditional Probability [07/14/1998]

If a sample has one element, what is its standard deviation? Also, can you help me with a conditional probability problem?

Standard Deviation and Units [04/02/2003]

When calculating standard deviation of a data set with units of measure (i.e. centimeters, liters, etc.), is the calculated standard deviation a 'unitless' value or does it include units of measure?

Standard Deviation Formula without Mean [10/03/2002]

Is there a formula for calculating the standard deviation without using the mean?

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