A business investigator has surveyed 23 supermarkets and recorded price changes of chocolate eggs after Easter. The average percentage change of the price is -22% with sample standard deviation of 25.9%.

1. What is the sample size of the data?

2. A newspaper claims that chocolate egg's price would drop less than 20% after Easter. Note: price drop by 20% means price change by -20%

Test the newspaper's claim by using the p-value method at 5% significance level.You need to

(a) justify your testing approach, (b) define any new notations properly, (c) state the null and alternative hypotheses, (d) show proper statistic for the test and steps of derivation, (e) make decision for the test and add a brief interpretation.