Name: Divesh Pradhan
Roll no: 2526-1195-31
Date: 8/24/2025
Sub: Statistics
Q)
The lifetime of electric bulbs for a
random sample of 10 from a large consignment gave the following data:
Item 1 2 3 4 5 6 7 8 9 10
Life
in ‘000 hrs 4.2 4.6 3.9 4.1 5.2 3.8 3.9 4.3 4.4 5.6
Can we accept the hypothesis that there
is no significant difference in the sample mean and the hypothetical population
mean, μ=4.
(2nd part
– if hypothetical population mean, μ=6)
Sample Data (in 000 hours)
[4.2, 4.6, 3.9, 4.1, 5.2, 3.8, 3.9, 4.3, 4.4, 5.6]
Sample Statistics
Sample size (n) = 10
Sample mean (x̄) = 4.40
Sample standard deviation (s) = 0.589
Degrees of freedom (df) = 9
Part 1: Hypothesized Mean μ = 4
H₀: μ = 4 (no significant difference)
H₁: μ ≠ 4 (significant difference)
Test statistic: t = 2.148
p-value = 0.0602
Decision: At α = 0.05, Fail to reject H₀. (Conclusion: The sample mean does not differ
significantly from 4.)
Part 2: Hypothesized Mean μ = 6
H₀: μ = 6 (no significant difference)
H₁: μ ≠ 6 (significant difference)
Test statistic: t = -8.593
p-value = 0.000012
Decision: At α = 0.05, Reject H₀. (Conclusion: The sample mean differs significantly
from 6.)