Assume that the swim times for the 25-yard freestyle are normal. Step 4 - Enter the level of significance. Conduct a hypothesis test using a preset α = 0.05. If the p-value is less than the significance level, we reject the null hypothesis. Frank thought that the goggles helped Jeffrey to swim faster than the 16.43 seconds. Inputs are: a sample estimate of the proportion. For the 15 swims, Jeffrey’s mean time was 16 seconds. P-values can be calculated for one or two-tailed comparisons and are compared to a specified significance level. Frank bought Jeffrey a new pair of expensive goggles and timed Jeffrey for 15 25-yard freestyle swims. His dad, Frank, thought that Jeffrey could swim the 25-yard freestyle faster using goggles. Jeffrey, as an eight-year old, established a mean time of 16.43 seconds for swimming the 25-yard freestyle, with a standard deviation of 0.8 seconds. The p-value is a number between 0 and 1 and is interpreted against a desired level of significance (.05) as follows: Value.
The calculator returns the t-test statistic and p-value. A p value (probability value) is used in hypothesis testing to determine the statistical significance of what a sample is telling you about a population. The following examples illustrate a left-, right-, and two-tailed test. Look for these key words to help set up your Hypotheses: Two-tailed Test. NOTE: If the p-value <, reject the null hypothesis otherwise.
This makes the data analyst use judgment rather than mindlessly applying rules. Use the TI-83 calculator to test the hypothesis that the population mean is not. This calculator will tell you the one-tailed (right-tail) probability value for a chi-square test (i.e., the area under the chi-square distribution from the chi-square value to positive infinity), given the chi-square value and the degrees of freedom. Similarly, for a large p-value such as 0.4, as opposed to a p-value of 0.056 (alpha = 0.05 is less than either number), a data analyst should have more confidence that she made the correct decision in not rejecting the null hypothesis. p-Value Calculator for a Chi-Square Test. Thinking about the meaning of the p-value: A data analyst (and anyone else) should have more confidence that he made the correct decision to reject the null hypothesis with a smaller p-value (for example, 0.001 as opposed to 0.04) even if using the 0.05 level for alpha.H a never has a symbol that contains an equal sign.It is the key to conducting the appropriate test. The alternative hypothesis, H a, tells you if the test is left, right, or two-tailed.For this reason, we call the hypothesis test left, right, or two tailed. When you calculate the p-value and draw the picture, the p-value is the area in the left tail, the right tail, or split evenly between the two tails.If no level of significance is given, a common standard to use is α = 0.05.The statistician setting up the hypothesis test selects the value of α to use before collecting the sample data.In a hypothesis test problem, you may see words such as “the level of significance is 1%.” The “1%” is the preconceived or preset α.Conduct and interpret hypothesis tests for a single population proportion.