A sample of a radioactive isotope had an initial mass of 800 mg in the year 2000 and decays exponentially over time. A measurement in the year 2005 found that the
şample's mass had decayed to 190 mg. What would be the expected mass of the
sample in the year 2009, to the nearest whole number?

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