## How do you find the mean and standard deviation?

1. The standard deviation formula may look confusing, but it will make sense after we break it down.
2. Step 1: Find the mean.
3. Step 2: For each data point, find the square of its distance to the mean.
4. Step 3: Sum the values from Step 2.
5. Step 4: Divide by the number of data points.
6. Step 5: Take the square root.

How do you find probability given mean and standard deviation?

In a normally distributed data set, you can find the probability of a particular event as long as you have the mean and standard deviation. With these, you can calculate the z-score using the formula z = (x – μ (mean)) / σ (standard deviation).

### How do you know if you have PA or B?

If events A and B are mutually exclusive, then the probability of A or B is simply: p(A or B) = p(A) + p(B).

What is the probability of A and B dependent?

If A and B are dependent events, then the probability of A happening AND the probability of B happening, given A, is P(A) × P(B after A). Example: A purse contains four \$5 bills, five \$10 bills and three \$20 bills.

## What is my independent and dependent variable?

Independent vs Dependent Variables An independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable. A dependent variable is the variable being tested and measured in a scientific experiment.

What is the probability that A or B occurs?

= 0. The probability that Events A or B occur is the probability of the union of A and B. The probability of the union of Events A and B is denoted by P(A ∪ B) . If the occurrence of Event A changes the probability of Event B, then Events A and B are dependent.

### How do you know if a variable is independent?

You can tell if two random variables are independent by looking at their individual probabilities. If those probabilities don’t change when the events meet, then those variables are independent. As a simple example, let’s say you have two random variables X and Y. X can equal 0, 1, or 2 and Y can equal 0 or 1.

What does it mean if two variables are independent?

The first component is the definition: Two variables are independent when the distribution of one does not depend on the the other. If the probabilities of one variable remains fixed, regardless of whether we condition on another variable, then the two variables are independent.

## How do you find the probability of two variables?

Just multiply the probability of the first event by the second. For example, if the probability of event A is 2/9 and the probability of event B is 3/9 then the probability of both events happening at the same time is (2/9)*(3/9) = 6/81 = 2/27.

How do you find the probability of an OR event?

The probability of an event is the number of favorable outcomes divided by the total number of outcomes possible. Converting the fraction 35 to a decimal, we would say there is a 0.6 probability of choosing a banana.

### How do you determine if two variables are independent?

Independence two jointly continuous random variables X and Y are said to be independent if fX,Y (x,y) = fX(x)fY (y) for all x,y. It is easy to show that X and Y are independent iff any event for X and any event for Y are independent, i.e. for any measurable sets A and B P( X ∈ A ∩ Y ∈ B ) = P(X ∈ A)P(Y ∈ B).

How do you find the probability of at least one?

To find the probability of at least one of something, calculate the probability of none and then subtract that result from 1. That is, P(at least one) = 1 – P(none).

## How do you find the sample mean from population mean and standard deviation?

The mean of the sample mean ˉX that we have just computed is exactly the mean of the population. The standard deviation of the sample mean ˉX that we have just computed is the standard deviation of the population divided by the square root of the sample size: √10=√20/√2.

What is independent variable in probability?

Independent Events: Two events A and B are said to be independent if the fact that one event has occurred does not affect the probability that the other event will occur. If whether or not one event occurs does affect the probability that the other event will occur, then the two events are said to be dependent.

### What is the meaning of independent variable?

Answer: An independent variable is exactly what it sounds like. It is a variable that stands alone and isn’t changed by the other variables you are trying to measure. For example, someone’s age might be an independent variable.

What is the difference between dependent and independent variable in research?

The independent variable is the variable the experimenter manipulates or changes, and is assumed to have a direct effect on the dependent variable. The dependent variable is the variable being tested and measured in an experiment, and is ‘dependent’ on the independent variable.

## What is independent variable in Research example?

In experimental research, the independent variable is manipulated or changed by the experimenter to measure the effect of this change on the dependent variable. Experiment example You are studying the impact of a new medication on the blood pressure of patients with hypertension.