Basic statistical analysis of a share of stock: Berkshire Hathaway Inc. Class A (BRK.A)
Shows how MS Excel can be used to perform a statistical analysis of empirical data.

Historical data: daily stock prices (Mar. 1980 to Feb. 2022) downloaded from Yahoo Finance.

• Range in days: 15,323
• Range (rounded) in years: 42

• Calculates the daily returns of the stock.
• Constructs a table with the descriptive statistics.
• Constructs a histogram of the returns (normal distribution.)
• Constructs a 95% and a 99% confidence interval for the mean return.
• Performs two sided hypothesis testing for the mean return (H0 is mean equals zero) at a significance level of 5%.
  • Computes the probability of a Type 1 error
  • Computes the probability of a Type 2 error assuming a mean return of 0.5%
• Assuming that returns follow the normal distribution, computes the probability of observing:
  • a daily return of less than -4%
  • a daily return of more than 2%
  • an annual return of less than -20%
  • a quarterly return of more than 7%
• Chooses a second random sample of 40 observations from base sample. Uses the RAND and VLOOKUP functions to automatically generate the sample.
• Calculates the number of days for which the return of the stock is positive or zero (uses the IF function). Tests the hypothesis that the proportion is equal to 50% (at a significance level of 5%.)