Statistics generally deals with quantitative data, i.e., data that can be expressed numerically. However, even qualitative data can be analyzed with statistics. Data might not always be quantitative in nature, as far as real life situations are concerned. Therefore, there is a need for a method for analyzing qualitative date as well.
One such method that can be used for analyzing qualitative data is Chi-squared method. Students studying statistics are often given Chi-squared statistics homework. For doing this test, two or more attributes needs to be considered. Then, you have to check if these attributes are associated or not.
Need for Chi-square test
Different tests of significance like F, Z and t are mainly based on the assumption that the samples are drawn from a normal distribution. Since these tests need assumption about population parameters, they are called parametric tests. However, while drawing samples, there might be situations where making a firm assumption about distribution of population might not be possible. As a result of this, non-parametric tests have been developed. Chi-square test serves as a prominent example of a non-parametric test.
Chi-square test is amongst the most commonly used and simplest non-parametric test in statistics. This is why Chi-squared statistics homework is commonly given to students. This test is denoted by the Greek letter x2. This quantity describes discrepancy theory magnitude and observation.
Chi-squared test can be defined as a statistical hypothesis test where sampling distribution is a chi-squared distribution of test statistic when null hypothesis is true. Chi-squared tests are usually constructed from sample variance or sum of squared errors. Independent normally distributed data is assumed for tests statistics following chi-squared distribution, which is valid for a lot of cases because of central limit theorem.
Degrees of Freedom
When you are doing Chi-squared statistics homework, you will be required to determine degrees of freedom for comparing between the table value and calculated value of x2. This is why it is extremely vital what degree of freedom actually means. It basically means the number of classes to which arbitrary values can be assigned without the placed restriction being violated.
X2, Chi-square statisticâ€™s sampling distribution can be approximated closely by chi-square distribution, which is a continuous curve. The number of degrees of freedom â€˜vâ€™ is the only parameter of this distribution. The probability function of this method depends on this â€˜v.’ With a change in the degrees of freedom, the probability function of Chi-square method also changes.
The distribution is skewed to right for small number of degree of freedom. With an increase in this number, the curve becomes more symmetrical on a rapid basis, until a large value is reached. At this point, the distribution can be approximated by normal distribution.
Applications of the test
Important applications of chi-squared test include:
Validity conditions for Chi-squared test
If you are given Chi-squared statistics homework, you need to know about the conditions which need to be satisfied for using Chi-square test. These include:
Steps involved in Chi-square test
The steps required to perform a Chi-squared test are rather simple, which is why it is a powerful statistical tool. This test can be used for analyzing a huge variety of data types. It is particularly useful when an analyst wishes to compare a percentage of items distributed among different categories. The steps mentioned below describes the method for computing Chi-square value and determining the statistical significance of that value:
By simply following the steps mentioned above, you can use Chi-square test for analyzing certain changes that might have occurred. You can use the data for determining the reasons for these changes.
Availing online help for Chi-squared tests
Homework related to statistics can be difficult, in particular, the Chi-squared statistics homework. It is easy for students to get confused and overwhelmed by the test, considering the number of steps involved in the process. If you are stuck with your homework related to Chi-square test, you can always consider seeking some help on the Internet through online homework help services.
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