A scientist for a company that manufactures processed food wants to assess the percentage of fat in the company's bottled sauce. The advertised percentage is 15%. The scientist measures the percentage of fat in 20 random samples. Previous measurements found that the population standard deviation is 2.6%.
The scientist performs a 1-sample Z-test to determine whether the fat percentage differs from 15%.
The null hypothesis states that the mean of the percentage of fat equals 15%. Because the p-value is 0.012, which is less than the significance level of 0.05, the scientist rejects the null hypothesis. The results indicate that mean percentage of fat differs from 15%.
N | Mean | StDev | SE Mean | 95% CI for μ |
---|---|---|---|---|
20 | 16.460 | 2.258 | 0.581 | (15.321, 17.599) |
Null hypothesis | H₀: μ = 15 |
---|---|
Alternative hypothesis | H₁: μ ≠ 15 |
Z-Value | P-Value |
---|---|
2.51 | 0.012 |