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In: Statistics and Probability

A noted psychic was tested for ESP. The psychic was presented with 220 cards face down...

A noted psychic was tested for ESP. The psychic was presented with 220 cards face down and was asked to determine if the card was one of 5 symbols: a star, cross, circle, square, or three wavy lines. The psychic was correct in 52 cases. Let ?p represent the probability that the psychic correctly identifies the symbol on the card in a random trial. Assume the 220 trials can be treated as an SRS from the population of all guesses.
To see if there is evidence that the psychic is doing better than just guessing, we test

?0: ?=.2
??: ?>.2

(a) What is the ?-statistic for this test?  

(b) What is the P-value of the test?

A recent poll of 2500 randomly selected 18-25-year-olds revealed that 290 currently use marijuana or hashish. According to a publication, 12.5 % of 18-25-year-olds were current users of marijuana or hashish in 1997. Do the data provide sufficient evidence to conclude that the percentage of 18-25-year-olds who currently use marijuana or hashish has changed from the 1997 percentage of 12.5%? Use ?=0.05 significance level.

test statistic z=

positive critical ? score=

negative critical ? score =

An article in the Washington Post on March 16, 1993 stated that nearly 45 percent of all Americans have brown eyes. A random sample of ?=80 C of I students found 30 with brown eyes.
We test

?0: ?=.45
??: ?≠.45

(a) What is the z-statistic for this test?  

(b) What is the P-value of the test?   

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