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Review the lesson about Midrange of a data set carefully before taking this quiz. When answering questions, keep in mind that there may be more than 1 correct answer.

Review the lesson about mode of a data set carefully before taking this quiz. When answering questions, keep in mind that there may be more than 1 correct answer.

Review the lesson about median of a set of data carefully before taking this quiz. When answering questions, keep in mind that there may be more than 1 correct answer.  

Review the lesson about mean from a frequency table carefully before taking this quiz. When answering questions, keep in mind that there may be more than 1 correct answer.  

Review the lesson about Arithmetic mean carefully before taking this quiz. When answering questions, keep in mind that there may be more than 1 correct answer.  

Review the lesson about Types of variables carefully before taking this quiz. When answering questions, keep in mind that there may be more than 1 correct answer.  

Review the lesson about Variable, element, data set, and observation carefully before taking this quiz.    

Review the lesson about Common sampling methods carefully before taking this quiz.    

Review the lesson about representative sample carefully before taking this quiz.    

Review the lesson about what is a survey carefully before taking this quiz.    

Review the lesson about population versus sample carefully before taking this quiz.    

Review the lesson about types of statistics carefully before taking this quiz.    

Review the lesson about what is statistics carefully before taking this quiz    

Just like quartiles, percentiles and percentile rank are among the measures of position. Percentiles divide a ranked data (ordered set of data ) into 100 equal parts. 99 percentiles are needed to divide any data set into 100 equal parts. The data should be ranked in increasing order to compute percentiles. The kth percentile is […]

Quartiles and interquartile range are among the measures of position. Just like the name indicates, quartiles divide a ranked data (ordered set of data ) into four equal parts. Only three measures are needed to divide any data set into four equal parts. These three measures that will divide an ordered data set into four […]

Here we show some examples of binomial experiments. But before we do so, what is a binomial experiment? When an experiment satisfies the following four conditions, the experiment is called a binomial experiment. Now, we will show a couple of good examples of binomial experiments to illustrate the concept. Example #1 Consider the experiment of […]

Find here some normal distribution word problems or some applications of the normal distribution. Example #1 Suppose the current annual salary of all teachers in the United States have a normal distribution with a mean of 51000 dollars and a standard deviation of 6000 dollars. Find the probability that the  annual salary of a randomly […]

Finding the z-scores for a specified area is the reverse procedure of finding the area under the normal curve. You will again need the standard normal distribution table Example #1 Find a point z such that the area under the standard normal curve between 0 and z is 0.3749 and the value of z is […]

Standardizing a normal distribution is to convert a normal distribution to the standard normal distribution. In real-world applications, a continuous random variable may have a normal distribution with a value of the mean that is different from 0 and a value of the standard deviation that is different from 1. In this case, we need […]

Learn how to calculate the area under the standard normal curve. This is an important skill, so study the following examples carefully. You will need the standard normal distribution table to solve problems. So go ahead and print the table and come back here. Example #1 Find the area under the curve between z = […]

Here is the standard normal distribution table. The entries give the areas under the standard normal curve from 0 to z. z    .00              .01            .02             .03             .04             .05  […]

The standard normal distribution (SND) is a special case of the normal distribution. When a normally distributed variable has a mean of 0 and a standard deviation of 1, we call this distribution standard normal distribution.   The random variable is denoted by z. In other words, notice that we use z instead of x […]

The normal probability distribution, also called normal curve, is a special type of bell-shaped curve like the one you see here. A continuous random variable is normally distributed either exactly or approximately. For example, scores on examination and heights of people are normally distributed. Characteristics of a normal distribution a. The total area under the […]

The continuous probability distribution is a table that shows the frequency and relative frequency of a continuous random variable. Recall that a continuous random variable can take any value over an interval or intervals. For example, suppose students have 60 minutes to finish a test. The time it takes students to finish the test can […]

The mean of the sampling distribution of x̄ (also called mean of x̄) is the mean of all possible sample means. In the lesson about sampling distribution, we ended up with the following sampling distribution of x̄  x̄  P(x̄) 83.33  0.10 85  0.20 85.66  0.20 86.66  0.10 87.33  0.20 89  0.20 ∑P(x̄) = 1 What if […]

This lesson will show the difference between sampling and nonsampling errors. Using a sample in order to get information about a population is often better than conducting a census for many reasons. Sampling is less costly and it can be done more quickly than a census which requires data for the entire population. However, as […]

As stated in the previous lesson, the population mean is always constant.  However, different samples of the same size drawn from the population will yield different values for the sample mean or x̄ .  Consequently, the sample mean, x̄ , is a random variable and just like any other random variables, the sample mean x̄ has […]

The population distribution is the probability distribution using all elements of a population. Suppose there are 5 students in a math class and their scores on the final exam are 80           85          85         90           92 The 5 scores above are the scores for the population since we are using all 5 scores. Let x be […]

The Poisson probability distribution is named after the French mathematician Simeon D. Poisson. Suppose there is a power outage in an apartment complex 3 times a year. You may want to find the probability that there will be exactly 2 power outage next year. This is an example of a Poisson probability distribution problem. Each […]

Here is a list of the types of averages used in statistics also called or measures of central tendency. We start with the common type. The most common types of averages are the mean, median, and mode. Mean The mean is found by adding all the numbers in a list and then divide by how […]

Summation notation is used to denote the sum of values. Suppose you have a sample consisting of the ages of 5 students in a middle school. Suppose the ages of these five students are 12, 14, 15, 10,  and 9 The variable age of a student can be denoted by x You could write the […]

Suppose we are selecting a few items from a large number of distinct items and you are trying to find out how many different ways this can be done. You are trying to find the number of combinations. Suppose you want to buy 2 cars from a set of 4 distinct choices. Suppose the set […]

We define the factorial of a number as the multiplication of all integers from that number to 1. We use the symbol ! which is an exclamation mark to denote factorial and we put the exclamation mark next to a number. For example,  5!  is read as five factorial and we can evaluate 5! by multiplying […]

The standard deviation of a discrete random variable is denoted by σ and the formula to use to compute it is σ =      or  σ =     We can use the example in the previous lesson about the number of people going to the movie theater each week to look for the standard deviation. We will […]

The mean of a discrete random variable x is the average value that we would expect to get if the experiment is repeated a large number of times. The mean is denoted by μ and obtained using the formula μ = ΣxP(x) Another name for the mean of a discrete random variable is expected value. The […]

The probability distribution of a discrete random variable shows all possible values a discrete random variable can have along with their corresponding probabilities. You could use a table to organize the information. In the lesson about discrete random variable, you conducted a survey asking 200 people about the number of vehicles they own. You came […]

Before giving a definition for discrete random variable, let us define random variable. A random variable is a variable that has exactly 1 numerical value and this value is determined by the outcome of a random experiment. For example, the number of vehicles someone owns is a random variable. To find out, you will need […]

Using the addition rule for probability, we will show you how to find the probability of the union of two events. We will use the table below about students who are gifted and those who are not. What is the probability that a randomly chosen student is gifted or male? First, we need to know […]

When you get the probability of the intersection of two events, we call this probability joint probability. Let A and B be two events in a sample space. The intersection of A and B is the collection of all outcomes that are common to both A and B. We can denote the intersection of A […]