KCSE Questions
1. Every week the number of absentees in a school was recorded. This was done for 39 weeks these observations were tabulated as shown below.
Number of Absentees | 0.3 | 4-7 | 8-11 | 12-15 | 16-19 | 20-23 |
---|---|---|---|---|---|---|
Number of Weeks | 6 | 9 | 8 | 11 | 3 | 2 |
Estimate the median absentee rate per week in the school
2. The table below shows high altitude wind speeds recorded at a weather station in a period of 100 days.
Wind Speed (knots) | 0-19 | 20-39 | 40-59 | 60-79 | 80-99 | 100-119 | 120-139 | 140-159 | 160-179 |
---|---|---|---|---|---|---|---|---|---|
Frequency (days) | 9 | 19 | 22 | 18 | 13 | 11 | 5 | 2 | 1 |
(a) On the grid provided draw a cumulative frequency graph for the data
(b) Use the graph to estimate
(i) The interquartile range
(ii) The number of days when the wind speed exceeded 125 knots
3. Five pupils A, B, C, D and E obtained the marks 53, 41, 60, 80 and 56 respectively. The table below shows part of the work to find the standard deviation.
Pupil | Mark (x) | x – a | (x – a)² |
---|---|---|---|
A | 53 | -5 | |
B | 41 | -17 | |
C | 60 | 2 | |
D | 80 | 22 | |
E | 56 | -2 |
(a) Complete the table
(b) Find the standard deviation
4. In an agricultural research centre, the length of a sample of 50 maize cobs were measured and recorded as shown in the frequency distribution table below.
Length (cm) | Number of Cobs |
---|---|
8 – 10 | 4 |
11 – 13 | 7 |
14 – 16 | 11 |
17 – 19 | 15 |
20 – 22 | 8 |
23 – 25 | 5 |
5. The table below shows the frequency distribution of masses of 50 new- born calves in a ranch.
Mass (kg) | Frequency |
---|---|
15 – 18 | 2 |
19 – 22 | 3 |
23 – 26 | 10 |
27 – 30 | 14 |
31 – 34 | 13 |
35 – 38 | 6 |
39 – 42 | 2 |
(a) On the grid provided draw a cumulative frequency graph for the data
(b) Use the graph to estimate
(i) The median mass
(ii) The probability that a calf picked at random has a mass lying between 25 kg and
28 kg.
6. The table below shows the weight and price of three commodities in a given
period
Commodity | Weight | Price Relative |
|
---|---|---|---|
X | 3 | 125 | |
Y | 4 | 164 | |
Z | 2 | 140 |
Calculate the retail index for the group of commodities