From a shipment of 350 light-bulbs, a sample of 70 was selected at random and tested. If 21 light-bulbs in the sample were found to be defective, how many defective light-bulbs would be expected in the entire shipment?
its not that
since you're sampling a fifth of the light-bulbs, then you would times 21 and 5 to get 105 defective light-bulbs
Since 70 bulbs is 1/5 of all the light-bulbs,then 21*5=105 will be defective.
To determine the expected number of defective light-bulbs in the entire shipment, we can use the concept of proportion. We know that out of the selected random sample of 70 light-bulbs, 21 were found to be defective.
First, let's calculate the proportion of defective light-bulbs in the sample:
Proportion of defective light-bulbs in sample = Number of defective light-bulbs in sample / Total number of light-bulbs in sample
Proportion of defective light-bulbs in sample = 21 / 70
Now, we can use this proportion to estimate the number of defective light-bulbs in the entire shipment:
Number of defective light-bulbs in entire shipment = Proportion of defective light-bulbs in sample * Total number of light-bulbs in shipment
Number of defective light-bulbs in entire shipment = (21 / 70) * 350
Let's calculate the estimated number of defective light-bulbs in the entire shipment:
Number of defective light-bulbs in entire shipment = (21 / 70) * 350
Number of defective light-bulbs in entire shipment = 0.3 * 350
Number of defective light-bulbs in entire shipment = 105
Therefore, it is estimated that there would be 105 defective light-bulbs in the entire shipment.