Moderate# Precision vs. Accuracy for Physical Properties

APCHEM-WSLUX3

Two students are working on an AP Chemistry lab. Their assignment is to determine experimentally the density of a nonvolatile organic liquid, limonene. The accepted value for the density of limonene is 0.8422 g/mL. Each student conducts three separate density determinations and then calculates a mean (average) value for the density and the standard deviation for their three trials.

The results and calculations for each student are shown in the table below.

Student A | Student B | |
---|---|---|

Density #1 | 0.8421 g/mL | 0.8408 g/mL |

Density #2 | 0.8514 g/mL | 0.8502 g/mL |

Density #3 | 0.8355 g/mL | 0.8332 g/mL |

Mean Density | 0.8430 g/mL | O.8414 g/mL |

Standard Deviation | 0.0080 | 0.0085 |

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Of the four descriptions given below, which of the following **BEST** interprets the accuracy and precision of Student A and Student B?