Question

Some species of garter snakes have a much higher proportion of males than females. A biologist wants to test the hypothesis that 75% of a certain species' population is male, believing the actual proportion to be higher. In a sample of 200 snakes, 162 were male, leading to a sample proportion of ?̂ =0.81 or 81%. Because there were more than 15 successes and failures for this test, a binomial approximation to the normal distribution was used. The following test statistic was calculated for a one-sample test for a proportion.

= = 196

Using software and the given ?‑statistic, calculate the ?-value.

For help using software, you might find this list of manuals useful. Please give your answer in decimal form, precise to three decimal places.

?‑value =

Answer 1

The statistical software output for this problem is:

One sample proportion summary bypothesis test: p: Proportion of successes HP=0.75 Hp>0.75 Hypothesis test results: Proportion Count Total Sample Prop. Std. Err. Z-Stat P-value P 162 200 0.81 0.030618622 1.9595918 0.025

From above output:

P - value = 0.025