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Let X denote the mass of pineapple tarts and $\mu$ denote the population mean mass of pineapple tarts.

$H_0: \mu = 0.9$

$H_1: \mu ~ \textless ~ 0.9$

Unbiased estimate of population mean = 0.8825

$s^2 = 0.0747854073^2 \approx 0.00559$ (3 SF)

Under $H_0, \bar{X} \sim \mathrm{N} (\mu, \frac{s^2}{n})$

Test Statistic, $T = \frac{\bar{X}- \mu}{\frac{s}{\sqrt{n}}} \sim t(7)$ at 10% level of significance.

Using GC, p-value $= 0.264619 > 0.1$

$\Rightarrow$, do not reject $H_0$

There is insufficient evidence at 10% significance level to reject the stall owner’s claim.

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