A) State whether each situation involves one-variable or two-variable data.
i) Marcus calculates the median mark of
the class on an exam.
ii) An article discusses the possible link
between prolonged cell phone use and the
increased probability of brain cancer.
iii) A classroom survey shows that 70% of the
students plan to attend university, 15% plan
to attend college, 10% are going directly into
the workplace, and 5% are uncertain.
b) Choose one situation from part a. Explain how
you
decided whether the situation involved
one- or two-variable data.

Arandom sample of 15 observations is used to estimate the population mean. the sample mean and the standard deviation are calculated as 172 and 63, respectively. assume that the population is normally distributed. a. with 99 confidence, what is the margin of error for the estimation of the population mean? b. construct the 99% confidence interval for the population mean. c. construct the 95% confidence interval for the population mean. d. construct the 83% confidence interval for the population mean. hint: you need to use excel function =t.inv.2t to find the value of t for the interval calculation.