In: Statistics and Probability
A study showed that 62% of supermarket shoppers believe supermarket brands to be as good as national name brands. To investigate whether this result applies to its own product, the manufacturer of a national name-brand ketchup asked a sample of shoppers whether they believed that supermarket ketchup was as good as the national brand ketchup.
b. If a sample of 100 shoppers showed 51
stating that the supermarket brand was as good as the national
brand, what is the p-value (to 4 decimals)?
we use concept of testing for the sample proportion based on the value of population proportion and by CLT we assume normality of the distribution.
Depending on the p-value whether it is greater or less than the level of significance alpha (0.05 or 0.01) we reject or accept the null hypothesis and claim whether the proportion who believes that super market brand or national brand are equivalent is less than 62%.