Stats ACT Math Review

Front

What is the formula to calculate a percentage of a number?

Back

To calculate a percentage of a number, use the formula: \( \text{Percentage} = \frac{\text{Part}}{\text{Whole}} \times 100 \% \) or \( \text{Part} = \text{Whole} \times \frac{\text{Percentage}}{100} \)

Front

What is the probability of an event?

Back

The probability of an event is a measure of the likelihood that the event will occur, calculated as: \( P(E) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} \)

Front

If a fair coin is flipped, what is the probability of getting tails?

Back

The probability of getting tails when flipping a fair coin is \( P(Tails) = \frac{1}{2} \) because there are two possible outcomes: heads or tails.

Front

How do you calculate the sale price after a discount?

Back

To calculate the sale price after a discount, use the formula: \( \text{Sale Price} = \text{Original Price} - (\text{Original Price} \times \text{Discount Rate}) \)

Front

What is the mean of a data set?

Back

The mean of a data set is calculated by adding all the numbers together and dividing by the total count of numbers: \( \text{Mean} = \frac{\text{Sum of all values}}{\text{Number of values}} \)

Front

What is the median of a data set?

Back

The median is the middle value of a data set when arranged in ascending order. If there is an even number of values, the median is the average of the two middle numbers.

Front

What is the mode of a data set?

Back

The mode is the value that appears most frequently in a data set. A data set may have one mode, more than one mode, or no mode at all.

Front

How do you find 40% of a number if you know 80% of it?

Back

If 80% of a number is known, you can find 40% by dividing the known value by 2. For example, if 80% = 122, then 40% = \( \frac{122}{2} = 61 \).

Front

What is a markdown in pricing?

Back

A markdown is a reduction in the original selling price of a product, often expressed as a percentage of the original price.

Front

How do you calculate the final price after multiple discounts?

Back

To calculate the final price after multiple discounts, apply each discount sequentially to the price after the previous discount. For example, if the price is reduced by 30% and then by 20%, calculate the new price after each discount.