Question

jayce is testing the effectiveness of a cell phone case made out of a new type of recycled plastic. he randomly samples 20 cases from every batch of 1,000 manufactured and tests their effectiveness at protecting a phone dropped from a set height. here are the data from one sample. test result frequency highly effective (no damage to case or phone) 9 moderately effective (damage to case only) 10 ineffective (damage to case and phone) 1 what percentage of the cases in this sample are rated as moderately or highly effective? %

Explanation:

Step1: Sum relevant frequencies

$9 + 10 = 19$

Step2: Calculate total sample size

$9 + 10 + 1 = 20$

Step3: Compute percentage

$\frac{19}{20} \times 100 = 95$

Answer:

95%