An electronic retailer believes that, at most 40% of their cellphone inventory was sold during november. the retailer surveyed 80 dealers and found that 38% of the inventory was sold. since 38% less than 40%, is the difference of 2 percentage points sampling error or a significant difference? test at .05 level.

Customers are used to evaluate preliminary product designs. in the past, 93% of highly successful products received good reviews, 51% of moderately successful products received good reviews, and 14% of poor products received good reviews. in addition, 40% of products have been highly successful, 35% have been moderately successful and 25% have been poor products. round your answers to four decimal places (e. g. 98.) what is the probability that a product attains a good review? (b) if a new design attains a good review, what is the probability that it will be a highly successful product? (c) if a product does not attain a good review, what is the probability that it will be a highly successful product?