In the case of Jessica Francisco’s paper, the research problem that the study examined the accuracy of identification of defective memory cards from a sample of cards that have been supplied. This resulted into the formulation of the null hypothesis and an alternative hypothesis. The null hypothesis stated that: Probability of finding a defective card was 1% of the cards supplied. The p-value that was used in this case is p = 0.01. The alternative hypothesis stated that: The probability of finding a defective card is 3% of the cards supplied. The z-value obtained was 4.9236 which was higher than the critical value of 2.575. Due to a high z-value, it indicates that the t-value fell far from the mean of 1% and that the null hypothesis was not true. Consequently, the null hypothesis was rejected. When 95 per cent confidence interval is used, it implies that when a sample of 95 memory cards are selected, it will result into a mean closer to the true mean of the total number of memory cards supplied ( Steinberg, 2011) . In a similar manner, a 99 per cent confident interval implies that when a sample of 99 memory cards are selected, it will result into a mean which is closer to the true mean of all the memory cards supplied.
In the study conducted by Lisa Farley, the purpose of the study was to determine the impact of using fidget spinner on the improvement of academic performance of learners. It was based on the view that the use of the fidget spinner has an impact of contributing to an eased post-traumatic stress disorder (PTSD), a reduction in anxiety, and a reduction in attention deficit hyperactivity disorder (ADHD) ( Lee, 2017) . The null hypothesis in this study was: there is no change in the grades of a student using fidget spinners. The alternative hypothesis was: fidget spinners increase grades. The expected finding was that children with fidget spinners were more likely to have improved grades. It will be expected that the z-value is greater than the critical z-score for the null hypothesis which shows that the scores of the children without fidget spinners is far away from the mean score. Due to this finding, the null hypothesis would be rejected. The alternative hypothesis would be accepted because it is expected that children who use the fidget spinners are experience low levels of anxiety, low level of PTSD, and low ADHD. 95 per cent confidence interval in this case implies that when a sample of 95 children’s grades are selected to calculate the mean score, it will result into a mean closer to the true mean grade of the entire population of children while 99 per cent confidence interval would imply that a sample of 99 children can enable obtaining a mean which is closer to the true mean of all the children’s grades.
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References
Lee, B. Y. (2017). Here’s the science behind the fidget spinner craze. Forbes. Retrieved from https://www.forbes.com/sites/brucelee/2017/05/19/heres-the-science-behind-the- fidget-spinner-craze/#6ac511233af0
Steinberg, W. J. (2011). Statistics alive! (2 nd ed.). Thousand Oaks, CA: Sage Publications.
