Final answer:
The electric toothbrush price values given are far below the mean, indicating an error. To calculate the correct proportion of prices in a normal distribution, one needs accurate values to compute the z-scores and find the proportion from a standard normal distribution table.
Step-by-step explanation:
The question involves finding the proportion of electric toothbrush prices that are between $104.60 and $108.20, given a normal distribution with a mean of $878.78 and a standard deviation of $88. The prices mentioned are significantly lower than the mean, likely indicating a typo or an error in the given values. Proper statistical analysis using z-scores cannot be applied with such values without correcting the error. However, assuming the question involves a correct set of values, you would calculate the z-scores for each price limit and then use a standard normal distribution table or a calculator to find the proportion between those z-scores.