2. How much of a radioactive substance must be presented to decay to 70 grams in 15 years if the half-life of the substance is 3.3 years? -Between 1300 and 1400 grams

-Between 1400 and 1500 grams

-Between 1500 and 1600 grams

-Over 1600 grams

1. why is a frequency distribution useful? it allows researchers to see the "shape" of the data. it tells researchers how often the mean occurs in a set of data. it can visually identify the mean. it ignores outliers. 2. the is defined by its mean and standard deviation alone. normal distribution frequency distribution median distribution marginal distribution 3. approximately % of the data in a given sample falls within three standard deviations of the mean if it is normally distributed. 95 68 34 99 4. a data set is said to be if the mean of the data is greater than the median of the data. normally distributed frequency distributed right-skewed left-skewed