MS 150 Statistics Fall 2000 Quiz Ten

Statistic Equations Excel
t-statistic or t-ratio or tdata xbartot.gif (1028 bytes) =STANDARDIZE(xbar.gif (842 bytes), m, s/SQRT(n))
t-critical  [ Excel TINV: If seeking a one tail probability, multiply alpha by two.  I do NOT recommend students use this function at this time, refer to your tables. ] Use table =TINV(two tail probability,degrees of freedom)
P-value from a t-statistic, degrees of freedom, and number of tails (1 or 2).   Note that the t-statistic must be the absolute value of the t-statistic.   Excel only accepts positive t-statistics. =TDIST(t-statistic,degrees of freedom, number of tails)

Open book quiz!  Use the formulas, tables, and figures in your book.

The population mean on a test was m = 9.02.  A group of 23 students taking the same test had a sample mean of 8.96 with a standard deviation of 2.69.  At an alpha of 0.05, is this sample mean different from the population mean?

  1. What is Ho?
  2. What is H1?
  3. What is alpha?
  4. What is the critical value for that alpha?
  5. What is the t-statistic for the data?
  6. Do we reject or fail to reject Ho?
  7. Optional: Find the p-value using Excel.

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