Answer:
b. yes type II error
Step-by-step explanation:
When the null hypothesis is false as is in this case and it is accepted so the decision made is wrong. This is a type II error.
When we accept the null hypothesis when actually it is false it is called a type II error.
In reality, the mean number of shades the toothpaste that whitens the teeth is three shades.
Where as the null hypothesis was that the four shades are taken as the mean number of shades the toothpaste whitens the teeth.
Therefore as the null hypothesis which is actually false is accepted so a wrong decision is made a type II error is made.
