Thursday, June 9, 2016

Statistical Data (Exercises)

Exercises.

TEST YOURSELF!!!

Click the link below:

Quantitative Data Vs Qualitative Data Exercises

Discrete Data Vs Continuous Data Exercises

Statistical Data Part V

Continuous Data

Continuous Data can take any value (within a range). the data that can be measured.

Examples:

A person's height: could be any value (within the range of human heights), not just certain fixed heights,
Time in a race: you could even measure it to fractions of a second,
A Cat's weight,
The length of a leaf,
The length of a paper

Statistical Data Part IV

Discrete Data

Discrete data can only take certain values. the only data that you can count.

Example 1: the results of rolling 2 dice:

Can only have the values 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12

Example 2:

Number of students taking this class.

Example 3:

Number of people who vote for a particular candidate in an election

Statistical Data Part III

Quantitative Data

Quantitative data is a numerical measurement expressed not by means of a natural language description, but rather in terms of numbers. However, not all numbers are continuous and measurable

Discrete data is counted,

Continuous data is measured

Qualitative data is a categorical measurement expressed not in terms of numbers, but rather by means of a natural language description. In statistics, it is often used interchangeably with "categorical" data.

Qualitative data is descriptive information (it describes something)

Example:

Your friends' favorite holiday destination
The most common given names in your town
How people describe the smell of a new perfume

Sastistical Data

What is Data?

Data is a collection of facts, such as numbers, words, measurements, observations or even just descriptions of things.

Qualitative vs Quantitative

Data can be qualitative or quantitative.

Qualitative data is descriptive information (it describes something)
Quantitative data, is numerical information (numbers).

Wednesday, June 8, 2016

Measure of Central Tendency (Exercise)

Exercises
1.The weekly salaries of six employees at McDonalds are $140, $220, $90, $180, $140, $200. For these six salaries, find:

(a) the mean
(b) the median
(c) the mode
Answer
2.Andy has grades of 84, 65, and 76 on three math tests. What grade must he obtain on the next test to have an average of exactly 80 for the four tests?

Answer

3.Test scores for a class of 20 students are as follows:
93, 84, 97, 98, 100, 78, 86, 100, 85, 92, 72, 55, 91, 90, 75, 94, 83, 60, 81, 95

Test Scores	Frequency
91-100
81-90
71-80
61-70
51-60

a) Copy and complete the table shown at the left.b) Find the modal interval.
The "modal interval" is the interval containing the greatest frequency. It is not the mode.
c) Find the interval that contains the median.

Answer

Measure of Central Tendency Part IV

The Mode

To find the mode, or modal value, first put the numbers in order, then count how many of each number. A number that appears most often is the mode.

Example:

3, 7, 5, 13, 20, 23, 39, 23, 40, 23, 14, 12, 56, 23, 29

In order these numbers are:

3, 5, 7, 12, 13, 14, 20, 23, 23, 23, 23, 29, 39, 40, 56

This makes it easy to see which numbers appear most often.

In this case the mode is 23.

Measure of Central Tendency Part III

The Median

The median is the middle score for a set of data that has been arranged in order of magnitude. The median is less affected by outliers and skewed data. In order to calculate the median, suppose we have the data below:

We first need to rearrange that data into order of magnitude (smallest first):

Our median mark is the middle mark - in this case, 56 (highlighted). It is the middle mark because there are 5 scores before it and 5 scores after it. This works fine when you have an odd number of scores, but what happens when you have an even number of scores? What if you had only 10 scores? Well, you simply have to take the middle two scores and average the result. So, if we look at the example below:

We again rearrange that data into order of magnitude (smallest first):

Only now we have to take the 5th and 6th score in our data set and divided with 2 then get a median of 55.5.

Measure of Central Tendency Part II

The Mean

The mean (or average) is the most popular and well known measure of central tendency. It can be used with both discrete and continuous data, although its use is most often with continuous data. The mean is equal to the sum of all the values in the data set divided by the number of values in the data set.

Mean: Add up the numbers and divide by how many numbers.

Examples:

Uncle Bob wants to know the average age at the party, to choose an activity.

There will be 6 kids aged 13, and also 5 babies aged 1.

Add up all the ages, and divide by 11 (because there are 11 numbers):

(13+13+13+13+13+13+1+1+1+1+1)

= 7.5

Measure of Central Tendency

Introduction

A measure of central tendency is a single value that attempts to describe a set of data by identifying the central position within that set of data. As such, measures of central tendency are sometimes called measures of central location. They are also classed as summary statistics. The mean (often called the average) is most likely the measure of central tendency that you are most familiar with, but there are others, such as the median and the mode.

The mean, median and mode are all valid measures of central tendency, but under different conditions, some measures of central tendency become more appropriate to use than others. In the following sections, we will look at the mean, mode and median, and learn how to calculate them and under what conditions they are most appropriate to be used.

Measure of central tendency

Mean
Median
Mode