Potato Weight E95482
1. **Problem statement:** We have a sample of 760 potatoes with weights measured and a cumulative frequency curve given. We need to find:
- (a) Number of potatoes weighing more than 200 grams.
- (b) Median weight.
- (c) Lower quartile.
- (d) Upper quartile.
- (e) Draw a box and whisker diagram using the given scale.
2. **Key concepts and formulas:**
- The cumulative frequency curve shows the number of potatoes with weight less than or equal to a given value.
- To find the number of potatoes with weight more than a certain value, subtract the cumulative frequency at that weight from the total number of potatoes.
- Median corresponds to the 50th percentile (760/2 = 380th potato).
- Lower quartile (Q1) corresponds to the 25th percentile (760/4 = 190th potato).
- Upper quartile (Q3) corresponds to the 75th percentile (3*760/4 = 570th potato).
3. **Step-by-step solution:**
**(a) Number of potatoes weighing more than 200 grams:**
- From the graph, cumulative frequency at 200 grams is approximately 425.
- Total potatoes = 760.
- Number weighing more than 200 grams = $760 - 425 = 335$.
**(b) Median weight:**
- Median position = 380th potato.
- From the graph, find the weight corresponding to cumulative frequency 380.
- The curve shows cumulative frequency 380 corresponds to about 190 grams.
- So, median weight $\approx 190$ grams.
**(c) Lower quartile (Q1):**
- Position = 190th potato.
- From the graph, cumulative frequency 190 corresponds to about 140 grams.
- So, lower quartile $\approx 140$ grams.
**(d) Upper quartile (Q3):**
- Position = 570th potato.
- From the graph, cumulative frequency 570 corresponds to about 280 grams.
- So, upper quartile $\approx 280$ grams.
**(e) Box and whisker diagram:**
- Minimum weight = 20 grams.
- Lower quartile = 140 grams.
- Median = 190 grams.
- Upper quartile = 280 grams.
- Maximum weight = 400 grams.
Draw a box from 140 to 280 grams with a line at 190 grams inside the box.
Draw whiskers from 20 to 140 grams and from 280 to 400 grams.
This diagram visually represents the distribution of potato weights.
**Final answers:**
- Number of potatoes weighing more than 200 grams: $335$
- Median weight: $190$ grams
- Lower quartile: $140$ grams
- Upper quartile: $280$ grams