Expected frequency is a statistical concept that is used to compare the observed frequency of a particular event to the expected frequency of the same event. It is used to quantify the degree of deviation from the expected frequency, and thus is a commonly used measure in hypothesis testing. This article will provide an overview of expected frequency and how it is used to assess the validity of hypotheses.
Expected frequency is calculated by first determining the probability of an event occurring. This probability is then multiplied by the total number of events expected to occur over a given period of time or sample size. For example, if the probability of flipping a coin and getting heads is 0.5, and the total number of coin tosses is 100, then the expected frequency of heads is 50. If the actual frequency of heads is greater than 50, then the result is considered statistically significant.
Expected frequency is commonly used in hypothesis testing to assess the validity of a hypothesis. For example, if a researcher wants to test whether a new phone model is more likely to drop calls than a previous model, they can calculate the expected frequency of dropped calls for each phone model. If the observed frequency of dropped calls for the new model is significantly higher than the expected frequency, then this provides evidence that the new model is more likely to drop calls than the old model.
Expected frequency can also be used to calculate the probability of an event occurring. If the expected frequency of an event is known, then the probability of the event occurring can be calculated by dividing the expected frequency by the total number of events. For example, if the expected frequency of heads in a coin toss is 50, then the probability of getting heads is 0.5.
Expected frequency is a powerful tool for hypothesis testing and assessing the probability of an event occurring. It is important to note that expected frequency does not necessarily imply causation, as other factors may be influencing the observed results.
References
Berenson, M. L., & Levine, D. M. (2014). Basic business statistics (13th ed.). Pearson Education.
Freedman, D., Pisani, R., & Purves, R. (2007). Statistics (4th ed.). W.W. Norton & Company.
Tate, P. (2007). Statistics: A guide to the use of statistical methods in the physical sciences (3rd ed.). John Wiley & Sons.