Confidence Intervals for the Mean When σ Is Unknown

Today i will teach you about Confidence Intervals for the Mean When σ Is Unknown When σ is known and the sample size is 30 or more, or the population is normally distributed if the sample size is less than 30, the confidence interval for the mean can be found by using the z distribution, as shown in Section 7–1. […]

Confidence Intervals for the Mean When σ Is Known

Today I will teach you how to Calculate Confidence Intervals for the Mean When σ Is Known In order to compute the confidence interval for the mean when σ is known, there are two assumptions that must be met. Assumptions for Finding a Confidence Interval for a Mean When σ Is Known The sample is a random sample. […]

Confidence Intervals and Sample Size

Today I will tech you about  Confidence Intervals and Sample Size The main objective of this section is to explain the basics of estimating a parameter such as a mean, proportion, or variance. Sample measures (i.e., statistics) are used to estimate population measures (i.e., parameters). For example, a sample mean is used to estimate a […]

The Normal Distribution

Today I will teach you about The Normal Distribution Normal Distributions In mathematics, curves can be represented by equations. For example, the equation of the circle shown in Figure  is x2 + y2 = r2, where r is the radius. A circle can be used to represent many physical objects, such as a wheel or a gear. Even though it is not possible […]

Mutually Exclusive Events

Today, I will teach you about Mutually Exclusive Events Many problems involve finding the probability of two or more events. For example, at a large political gathering, you might wish to know, for a person selected at random, the probability that the person is a female or is a Republican. In this case, there are […]

Types of Sampling Methods

Today i will teach you types of sampling methods Random Sampling A random sample is a sample in which all members of the population have an equal chance of being selected. Random samples are selected by using chance methods or random numbers. One such method is to number each subject in the population. Then place numbered cards […]

Levels of Measurement – nominal, ordinal, interval scale

Today, i will teach you the four levels of measurement – nominal, ordinal, interval scale The first level of measurement is called the nominal level of measurement. A sample of college instructors classified according to subject taught (e.g., English, history, psychology, or mathematics) is an example of nominal-level measurement. Classifying survey subjects as male or female is […]

The boundary of a Number

Today i will teach you about the boundary of a number Since continuous data must be measured, answers must be rounded because of the limits of the measuring device. Usually, answers are rounded to the nearest given unit. For example, heights might be rounded to the nearest inch, weights to the nearest ounce, etc. Hence, […]

Types of Variables and Types of Data

Today i will teach you about the types of variables and types of data Variables can be classified as qualitative or quantitative. Qualitative variables are variables that have distinct categories according to some characteristic or attribute. For example, if subjects are classified according to gender (male or female), then the variable gender is qualitative. Other examples of qualitative […]

7 Assumptions of Linear regression using Stata

7 Assumptions of Linear regression using Stata There are seven “assumptions” that underpin linear regression. If any of these seven assumptions are not met, you cannot analyse your data using linear because you will not get a valid result. Since assumptions #1 and #2 relate to your choice of variables, they cannot be tested for […]