An agricultural scientist is investigating whether vacuum-sealing organic blueberries extends their shelf-life compared to standard ventilated containers. The shelf-life, $T\,$ days, was recorded for two independent random samples.

A random sample of 80 containers using standard ventilated packaging, and an independent random sample of 60 containers using vacuum-sealed packaging, were monitored. The results are summarized in the table below:

Sample Group	Sample size ( $n$ )	$∑T\sum T$	$∑T2\sum T^2$	Unbiased estimate of mean	Unbiased estimate of variance
Standard	80	960	12400	$Tˉ\bar{T}$	$s^2$
Vacuum-sealed	60	-	-	13.5	14.2

Find the values of $Tˉ\bar{T}$ and $s^2\,$ for the standard ventilated packaging.

Test, at the 1% level of significance, whether there is evidence that the mean shelf-life of the blueberries is greater when vacuum-sealed. State your hypotheses clearly.

Sample Group	Sample size ( $n$ )	$∑T\sum T$	$∑T2\sum T^2$	Unbiased estimate of mean	Unbiased estimate of variance
Standard	80	960	12400	$Tˉ\bar{T}$	$s^2$
Vacuum-sealed	60	-	-	13.5	14.2

Find the values of $Tˉ\bar{T}$ and $s^2\,$ for the standard ventilated packaging.

Test, at the 1% level of significance, whether there is evidence that the mean shelf-life of the blueberries is greater when vacuum-sealed. State your hypotheses clearly.

2.5.3 Hypothesis test for a Normal mean (A-level only)

Question 77

Markscheme

2.5.3 Hypothesis test for a Normal mean (A-level only)

Question 77

Markscheme

2.5.3 Hypothesis test for a Normal mean (A-level only)

Question 77

2.5.3 Hypothesis test for a Normal mean (A-level only) Questions

2.5.3 Hypothesis test for a Normal mean (A-level only)

Question 77

2.5.3 Hypothesis test for a Normal mean (A-level only) Questions