Question

Instructions: Decide which set of statistical procedures (Options A – E) should be used to answer the question presented in each problem. Circle your selection. Both ambiguous answers and incorrect answers will not receive credit (partial or full). Answer choices may be repeated or omitted.

A: One-sample Z-procedure

B: One-proportion Z-procedure

C: Two-sample Z-procedure

D: One-sample T-procedure

E: Two-sample T-procedure (including matched-pairs or two-independent samples)

Shawn Spencer is a psychic that works as a part-time consultant for the Santa Barbara Police Department. Detective Carlton Lassiter has doubts that Shawn really is psychic and decides to test him for ESP. In particular, Shawn was presented with 100 cards face down and for each card, he was asked to determine whether the card was one of four symbols: a star, a circle, a square, or a cross. Shawn was correct in 30 cases. Let < represent the probability that Shawn correctly identifies the symbol on the card in a random trial. Assume the 100 trials can be treated as an SRS from the population of all guesses Shawn would make during his lifetime. Which inference procedure would you use to determine whether Shawn is doing better than just guessing?

A OR B OR C OR D OR E

Answer 1

Here we have to use One-proportion Z-procedure.

Because we are interested in testing following hypothesis:

If Shawn is doing better than just guessing then probability of correct guessing is greater than 0.5.