Question

Assume an alpha of 0.05 unless otherwise specified. (note the due date)

1. A researcher would like to know if the average weight of two different species of birds is different so the collect random samples from each species. They compile the following information:

Species 1(n=67)

Mean of 453 grams with a standard deviation of 28 grams

Species 2(n=43)

Mean of 512 grams with a standard deviation of 32 grams

Do we have sufficient evidence to conclude that the means for the 2 species are different?

2. A wooden toy manufacturer is cutting lengths of wooden dowel to be used to assemble toys. The data is included in the attached excel file. Do we have sufficient evidence to conclude that the average length of the dowels are less than 3 inches?

3. A wooden toy manufacturer is cutting lengths of wooden dowel to be used to assemble toys. The data is included in the attached excel file. Do we have sufficient evidence to conclude that the variance in the length of the dowels is more than 0.025?

4. The toy manufacturer is comparing two different machines used to cut the dowels and would like to know if the variances between the two machines are the same. For the first machine they collect a random sample of 200 and calculate a variance of 0.03. For the second machine they collect a sample of 100 and calculate a variance of 0.035. Do they have sufficient evidence to conclude that the variances are different?  

5. A company is evaluating if a new configuration increases the battery life of laptops above the current average of 450 minutes. The company randomly selects a sample of laptops and collects the data included in the excel file. Can we conclude that the new configuration improves battery duration?

Length

3.15

2.76

3.18

2.77

2.86

2.66

2.86

2.54

3.02

3.13

2.94

2.74

2.84

2.60

2.94

2.93

3.18

2.95

2.86

2.91

2.96

3.14

2.65

2.77

2.96

3.10

2.82

3.05

2.94

2.82

3.21

3.11

2.90

3.05

2.93

2.89

Length

3.15

2.76

3.18

2.77

2.86

2.66

2.86

2.54

3.02

3.13

2.94

2.74

2.84

2.60

2.94

2.93

3.18

2.95

2.86

2.91

2.96

3.14

2.65

2.77

2.96

3.10

2.82

3.05

2.94

2.82

3.21

3.11

2.90

3.05

2.93

2.89

Battery

Life

315

463

462

206

275

432

585

650

545

547

508

580

Answer 1

1)