The number of text messages sent by 25 13-year-olds over the past month are as follows
1 answer:
Answer:
7 ; 19 ; 8% ; 28%
Step-by-step explanation:
Given the data:
791 542 671 672 555 582 616 961 639
691 648 967 959 826 573 598 790 954
711 515 649 960 949 802 507
How many of the 13-year-olds sent at least 600 but less than 700 text messages? = 7
c-2. How many sent less than 900 text messages? = (7 + 7 + 3 + 2) = 19
d-1. What percent of the 13-year-olds sent at least 800 but less than 900 text messages? =0.08 × 100 = 8% (from relative frequency)
d-5. What percent of the 13-year-olds sent less than 600 text messages? 0.28 × 100 = 28% (from relative frequency)
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Answer:
The decision rule for rejecting the null hypothesis is
Step-by-step explanation:
A manufacturer of potato chips would like to know whether its bag filling machine works correctly at the 410 gram setting. It is believed that the machine is underfilling the bags.
At the null hypothesis, we test if the mean weight of the bag is the desired value of 410, that is:
At the alternate hypothesis, we test if the bag is underfilled, that is, the mean weight is below the desired value, so:
Type of test:
As we test if the mean is less than a value, we have a left-tailed test.
We have the standard deviation for the sample, which means that the t-distribution is used.
We have 22 - 1 = 21 degrees of freedom, with a level of significance of 0.05.
Using a calculator, the critical value is
Determine the decision rule for rejecting the null hypothesis.
We reject the null hypothesis if the test statistic is less than the critical value, so the decision rule for rejecting the null hypothesis is